Archive Computer Monitor Repair

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Computer Monitor Repair - Archived Files (cont.)

Updated March 25, 2005

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QUESTION NO. P11003-4: Samsung SynkMaster 710s monitor FCC A3LCHB770. I need the value of D630..

I believe this is a 27 Volt Zener diode, added to protect IC601.

QUESTION NO. P10903-2: Gateway ev700-7000965 monitor, picture is blurry. There is some adjustment using the focus block on the flyback, but video is still not crisp.

Check heater voltage.

QUESTION NO. P20603-8: Sony CPD-200GST monitor chassis SCC-L07B-A. I need the type and value of D608.

D608 is type RD18ESB2, an 18 Volt Zener; it is Sony part number 8-719-110-49.

QUESTION NO. P20603-1: Sony SCC-L07G-A Chassis monitor (IBM 6556-43) with Q507 (HOT) and Q520 (MOSFET "H-REG OUT") blown. No bad solder joints.

Sometimes, only Q507 and Q520 are bad, but, besides the solder, you also might check D516 (200 Volt, 3 Amp, ultrafast), D518 (10 Volt zener), D506 (damper), C508, and C575.

QUESTION NO. P20603-2: Samsung 400nb monitor. When switched on b+ line drops but rises (when lopt end disconnected) to correct value. HOT tests ok. Is lopt faulty?

This does sound like a faulty LOPT.

QUESTION NO. P20403-1: Samtron 75e /DP17LT monitor. Replaced burnt R513 and it burnt again. Checked flyback and HOT OK. Removed Hor Def yoke. Replaced R513 again and it did not burn. I did a ring test on the yoke and it hit 6., which shows acceptable. Is the yoke possibly still bad or are there other parts of the circuit I should be checking?

This is part of the G2 circuit. Check D583 , C587, R589 , R588 , R522.

QUESTION NO. P20303-4: Dell D1226H monitor CM5800 chassis has no line drive vertical line on the screen. R3544 is open, I need the value and a reason for it over-heating and going o/c.

R3544 is 1 ohm. Also check Q7532 (HOT 2SC5331), Q7543 (P-channel Mosfet MTP5P25), D6534 (Damper BY459-1500), L5526. If the semi's are leaky or shorted, R3544 can open.

QUESTION NO. P13003-4: Acerview 56c monitor (7256c). I need value of R618 (0,5 ohm ?) and cross reference of Q602. I substituted Q602 with IRF840, but after 1 day it burned the resistor and mosfet.

R618 is 0.5 Ohm, 1 Watt, fusible. Q602 is 2SK2645, a 600 Volt, 9 Amp Mosfet (IRF840 is rated for 500 Volts). Possible crosses include IRFIB6N60A or STP11NM60FP, or with insulator, IRFB9N60A or STP11NM60; IRFBC40A might squeak by, but in this unit, you may not wish to risk it. Digikey (www.digikey.com) lists the IRF FET's, and Mouser (www.mouser.com) lists the STP FET's. Since Q602 has burned, you might also check R608, R609, D605, C624, and IC601, as well. If no zener is installed at location ZD605, in parallel with R608, and if problems still persist, you might consider installing an 18 to 20 Volt zener at location ZD605 as protection for the gate of Q602.

QUESTION NO. P12703-9: Gateway 2000 Crystalscan monitor Chassis YEO711-01. Power supply makes ticking noise but will not start.

This symptom is usually due to an overload. There are many potential causes of this, in this chassis, such as shorted diodes (D311 through D315; D102, D103, D104, etc.); shorted Q105 or cracked solder on Q105; shorted Q103 or Q203; shorted C108, C104, or C105, to name some.

QUESTION NO. P123002-3: Acer AJ15,FCC AMPJ51I Monitor no display and also no power LED indicated. Replaced shorted HOT (BU2520AF) and it shorted again and confirmed FBT 751-02-56 is shorted. I cannot find the original, what is the sub for this FBT.

I think there is no sub but try http://www.electronicsic.com

QUESTION NO. P10604-9: IBM 6547 monitor, transistor KSC 5088 Blown & IRFI 6530 . I replaced them & they blew again.

If you are not able to ring the flyback, unplug and short the tube top cap to the aquadag. Now measure resistance to chassis from top cap, any reading is bad news. Can also test for capacitance, nano farad OK 15 to 25 pF bad news.

QUESTION NO. P10703-5: Proview PX-986 monitor FCC IJE 986, Horizontal deflection shrinks to about 1/3 width. Returns to full width instantly when case is flexed. No flexing will bring it back. Digital Horizontal width control adjustment doesn't affect width.

Check 22mf 250volts cap on +B rail.

QUESTION NO. P11403-9: Samsung syncmaster 450b monitor, replaced defective transistor d2125.2e with BU 508 DF then every thing ok for 120 seconds maximum and then I hear sound like caps discharge then screen vibrates and monitor powers off itself. Now the screen is white with or without data signal and the same sound problem.

I think there is a flyback spark from body to ground, that is why the set goes dead after a few seconds. Replace FBT with new one.

QUESTION NO. P11403-7: Dell 828fi, horizontal, vertical width are too wide, controls are adjusting but do not fit picture into normal, osd menu is normal. I replaced tda9109 with used one but no change, suspect flyback.

Before changing the flyback, check C509 and C517; if not these, check if IC501 is functional, and providing pulses to Q506, which drives the B+ boost FET, Q504.

QUESTION NO. P121302-3: Dell 828fi monitor 800f series was shocking. I could not find any leakages but found C5088 is bad. What replacement can I use and what is the function and composition of this transistor?

The full number is KSC5088; it is a 1500 Volt, 8 Amp, 50 Watt, Horizontal Deflection transistor. NTE 2324 is one possible replacement, as are 2SC5299, 2SC4924, 2SC5386.

QUESTION NO. P10903-3: Acer 7276e FCC JVP 7276E. Need values of burnt R241, R329 (reads approx. 10.5K ohms), and C327 these all look as if caught on fire. Also checked ZD 210 shorted off pin 1 of IC 201 a TDA 4858. Number on diode is 1N 751A a 5.1 volt 1/2 watt. I also pulled C326 another ceramic with 271 a 270 pico farad capacitor. Also should I check anything else for possible damage as most of these are in the horizontal drive circuit?

R241 = 10k, R329 = 10k, C327 = 220pF 2KV. Check R326, R328, D309, Q317 hopefully ZD201 protected IC201.

C327 = 220 pF/2KV, ceramic disk cap; use a 3KV capacitor as replacement, if possible. C326 = 270 pF/500V. R241 = 10K, R329 = 10K, R326 = 3.9K, R328 = 4.7K. Also check the 3 Amp microfuse at location J013, the small MOSFET at location Q301 (BSS89), and HOT Q302 (2SC5048). If the 5.1V zener ZD201 has shorted, sometimes IC201 is also bad.

QUESTION NO. P10803-6: I need the part number and sub for Q2001 (N1l4M K34XM) of NEC XV17+ monitor.

That marking corresponds to AN1L4M, an NEC PNP digital switching transistor. There are two series 47K resistors between its base and emitter leads, which will make this device test differently from normal transistors. The NTE/ECG 2360 is a possible sub.

QUESTION NO. P10703-10:  Optiquest Q71.  R457 was burned, I need the value.

The resistor is 680 ohm 緩 R457in circuit.

There are several different chassis used in the Optiquest Q71, but if R457 burned, yours is probably the Jean chassis, where R457 is 680 ohms, 1/2 Watt. Also replace the defective disk capacitor C449 (220pF/2KV), which caused the R457 to burn.

QUESTION NO. P10603-5: Viewsonic G810 monitor started out by making a 'snapping' sound, then going out of focus, and picture (H&V) expanding past the crt borders momentarily. Symptom was intermittent. S671 (spark gap) was the source of the snapping, and is severely discolored. The monitor finally died completely while on the test bench. I suspect the FBT, TLFA01365. H.O.T. appears to be ok.

Flyback TLFA01365 is the most common failure in this chassis, and can cause those symptoms. To obtain this flyback, try a Panasonic distributor.

QUESTION NO. P:123002-3: Samsung dp17LT monitor. Need value for R513 which is burnt.

The schematic shows R513 as 27K ohms, 1/2 Watt.

QUESTION NO. P123002-7: Acer 7176ie monitor, video output IC102 is blown, all that is legible is LM?

The schematic shows IC102 as a LM2419.

QUESTION NO. P121602-9: Nokia 447e monitor, I need the value of burned R209.

2.2 ohms

QUESTION NO. P112202-4: Mag DX1795 Monitor has very bad pincushion. Checked caps and diodes.

Try to change TDA9103 or there is a small pincushion driver transistor Q516.

QUESTION NO. P121802-6: Hyundai HT-7770C monitor. I need the values of R308 and R309, both burned to an unreadable state. R308 connects to B+ sense-input of H/V-controller TDA4854. R309 is a fusible resistor between ground and source of FET Q304 (YTA630).

R308 is 1.5K ohms, and R309 is 0.47 ohms, 1 Watt. Since R308 and R309 burned, also check/replace D310, Q304, Q310, and the TDA4854 IC.Sometimes the cause is a faulty Q310 Mosfet that has become degraded, but not completely shorted.

QUESTION NO. P121602-4: Acerview 76e monitor (7276e) powers up with black screen and LED is on green. R241, R329 and R326 were burn, I have been checking the FBT, is it usual that the pins 1&2 in the FBT are doing contact with pins 6&7? Must these pins be open between 1-2&6-7?

The Acer schematic shows the FBT 1-2 winding as being separate from the 6-7 winding; I would suspect a bad FBT. With those three resistors bad, also replace C327 (220pF/3KV), and check Q301 (BSS89) Q302 (2SC5048), ZD210 (5.1 Volt), IC201 (TDA4858), R328 (4.7K), and the 3 Amp micro-fuse at location J013.

QUESTION NO. P112502-4: I have been getting a problem with the Viewsonic monitors that seem to use more then one kind of fbt in the same model. Is there a way to help me figure out what FBT to order by chassis? Viewsonic never goes by the number on the fbt itself, and I do not have Service Manuals for all of them. I have a couple of G810 monitors but do not know what FBT to get.

Typically, the Viewsonic "VCDTS" model number will end with a suffix, like -2A, -4M, etc, whose number indicates which revision of a given model, you have. For those Viewsonics which are Panasonic chassis (not all are), you can usually find a Panasonic chassis code on the PCB board edge, like HV8SA, HV10S, HV12S, GV3, GV3D, etc. This helps determine which FBT is needed. HV8SA uses FBT# ETF42L31AZ, HV10S uses FBT# TLFA01365, HV12S uses ETF40L48AZ, GV3 uses TLFA00965, etc. Note that some models, like GV3, need Viewsonic's software, to adjust the focus after replacing.

QUESTION NO. P112202-7: Mag DX15-T monitor has excessive, out of range width. Horizontal size & pincushion adjustment from on-screen menu have little effect.

Look for open resistors of low value & a diode mounted to a heat sink standing vertically which is probably open or short.

QUESTION NO. P112602-2: Philips Brilliance 107 monitor, model 17A8808q, chassis CM8800, FCC A3KM060 no picture. Replaced defective Component 7503 BU2527A and component 3518 1R, after a few hours, a day or a week the same components are again defective. I replaced lin. coil 5508 but that is not the problem. I have three of these monitors with the same problem.

Check all the B+ line caps and any 1-2KV ceramics in the deflection circuit have found these electrolytics to lose capacity totally causing HOT to blow & sometimes other parts.

QUESTION NO. P111902-8: HP Ergo 1280 model D2840A monitor FCC IEY447S has no picture only LED blinks then fades, fuse F103 (6.3Amp/250volt) is blown and next to it D131 (FEP16 BT ) is short circuit.

Check for shorts in all power semiconductors D, T and SCR. After repair, use a 40W light bulb in series with power line, then a 60W, then a 100W, then directly connected to power line. This is to avoid burning again all the parts that you'll have changed.

QUESTION NO. P111902-7: Acer 7276e monitor starts up with fussy blue retrace lines that disappear after about an hour. I changed a couple of capacitors by the flyback and still no change.

Check on the PCB connected to the tube neck's. Here you have R, G and B colors circuit's. Identify the blue circuit and compare each capacitors that you find with the ones similar the the red or green circuits. It could also be due to a heater-cathode short. But this would normally not disappear after an hour of use. You can also temporarily switch the color output circuits. Blue to red and red to blue then see what is happening on the screen.

QUESTION NO. P112602-6: Packard Bell A926 monitor. Replaced blown FBT Bu 4525Ax and FET J512. After about a half hour it starts overheating.

Overheating is normally due to a wrong polarization of power transistor or a defective damping or clipping diode. Check for changed value or bad R, C or D around the HOT and maybe the FET that you changed.

QUESTION NO. P112502-9: Gateway EV700 monitor FCC iawe7006. I need the value of R253. I think it has the Mag Chassis.

R253 is 10 ohms, 3 Watts.

QUESTION NO. P112502-10: Sony CPD-17sf2 monitor. I need the value of zener diode D505, located near Q503.

D505 is a 10 Volt zener.

QUESTION NO. P112202-6: Gateway EV-700-069EV monitor FCC BEJC780. Looking for the values of R798 and SG702 located near the flyback. Both are burnt beyond recognition. Is this the chassis that has a high failure rate for the flyback?

R798 is 10K, 1/2 Watt; SG702 is a 300 Volt spark gap. The schematic shows that these connect to a pin of the flyback, so I'd suspect that an overvoltage from the flyback damaged them.

QUESTION NO. P112202-5: I need the value of R502 and R503 for Hyundai DeluxScan 17B+ Model HL-7870A monitor.

I show R502 as 10K, and R503 as 5.1K. These are in the ABL circuit, so probably they burned due to a faulty flyback transformer, which also would need replacing.

QUESTION NO. P111902-2: Mag 1795 monitor, need to know the value of zd301. Monitor has been shelved for a while and this component appears to have been taken off the board.

ZD301 is an 18 Volt Zener.

QUESTION NO. P44-6: Silicon Graphics (Sony) GDM-20D11 monitor goes into standby mode immediately on switch -on. Can hear HT come on, so HOT is good. Power supply OK. Power lamp steady green, standby lamp also steady amber. There is a little switch in the back enabling "Test". When doing so, screen lights up and a blurred (no sync) picture is seen. Checked/replaced all the electrolytics on the DA-board. Could it be the monitor cable? It has the label C-133-6 for SUN monitor.

First, the SGI GDM-20D11 is a sync-on-green monitor, so be sure this sync is being provided by the computer. The 13W3 pinouts for SUN and SGI are not identical; at the following webpage, www.monitorworld.com/Cables/video_standards.html#13W3SGI you can get the pinouts of these cables, to compare with your own cable.

QUESTION NO. P44-4: Sony CPD-1425 monitor totally dead and no light on LED. I replaced HOT with BU2508A. What exactly HOT for that monitor? I replaced all electrolytic caps that were short or dried. FET is ok (I think). Fuseable Resistor is Ok too.

I think the HOT is BU2520 = 10 Amp (BU2508 = 8 Amp). Check for cracks in the board, by the flyback and repair any broken connections.

QUESTION NO. P42-8: AST RM07F11 monitor FCC GWGRMO-RT07FXX with high voltage, no video. Q302, zd 301, q350, c350 are gone. I need the value of ZD 301.

ZD301 is a 15 Volt zener. With those four components blown, it is advisable to resolder the large rectifier D303; also be sure its bottom lead extends entirely through the board, or add an extension wire if it was cut too short.

QUESTION NO. P42-2: Acer 1454e monitor keeps blowing HOT BU2508AX, why?

I would ring flyback. Check caps in voltage regulator circuit for high esr. Also check the driver transistor .I would sub it instead [they do loose gain and develop leakage]. Check voltage from regulator that it is not too high by subbing ho transistor with 25 w lamp connected where collector, emitter went. monitor the voltage at collector in respect to emitter. It should not be higher than power line voltage ie 158v. Probably around 120- 130 vmax from regulator if it's working right.

It sounds like this Acer may be similar to the Acer FCC# JVP7134e chassis. There are many possible causes for repeatedly blowing HOT's, but one common cause, in that chassis, is a bad disk cap (C335 = 220pF/2KV) on the AFC line to IC201. If R214 = 15K is also bad, then IC201 itself may be damaged as well. The horiz. drive cap C319 might be bad. Bad solder joints, such as on drive transistor Q315 or drive transformer T301, or bad connections for the FBT or yoke, are also potentially damaging to the HOT.

QUESTION NO. P327-4: CTX pl5a monitor FCC DBL1454EL with no video. I replaced D109 (burned) and R717. When power applied, a rare sound noise appear, in 20 second the resistor burns again.

If R717 has burned again, be suspicious of a defective flyback transformer. Also check associated components, R712, VR702, C721, and IC701 (TL431).

QUESTION NO. P328-9: Packard-Bell 1512 SME, LiteOn monitor came in with a refresh rate of about 20 Hz and all out of sync. I replaced the IC 93C56 with 93LC56, and the TDA9102 (which did not help) and the MTV003 (did not help). Now the 130 voltage is around 90 volts, the peak voltage of the HOT is around 750 volts. I cannot find any way to restore the voltages to normal. I think that because of the low voltages the picture is still out of sync.

If this LiteOn is FCC H4ICM15006, I trust that you used a pre-programmed Eeprom (the 93C56 chip) as your replacement, and that it was the correct version for your chassis. (The 130V can get reduced to around 88-90V, with a corrupt/defective/unprogrammed Eeprom.) If the Eeprom is good, then the next suspect is a defective microprocessor (IC701); again, be sure to use the correct version. It is helpful to apply a grounded heatsink to IC701, to protect it from thermal faults or arcing.

QUESTION NO. P328-1: Princeton eo70 monitor with R901 and R902 burned, I cannot identify their value.

This Princeton is a KDS (Korea Data Systems) chassis, FCC EVOKD-1730. In which case, R901 = 27K, and R902 = 12K. If these resistors burned, it was probably caused by a defective flyback transformer (KDS FBT# KFS61411A). This flyback has been a common failure in the Princetons, and in KDS models like KDS VS-7. They can be purchased either from Princeton, or directly from KDS for the KDS chassis.

QUESTION NO. P328-7: Princeton EO17 monitor FCC EVOKD-1730 with a shorted D406 causing the cir. board to burn open between it and C437 / (jumper)R410. It also has an overheated R304. I need the cross or sub / spec for D406 and value of R304 so I can obtain them locally. Also, are any other components in that area likely to need replacement / checking?

In a KDS FCC EVOKD-1730, D406 is Shindengen's D1NL20U, a 200V, 1 Amp, Trr < 35 nsec ultrafast rectifier; NTE/ECG 587 or 574 might substitute. R304 is 4.7 ohms, 1/2 watt. Also check/replace the vertical IC (IC301).

QUESTION NO. P326-3: Packard Bell 1512SL monitor. I need the part number of the function control chip thermal. Zilog 1570. It is positioned under the CRT and also any other chips that may be problems in this area.

I assume this 1512SL is the chassis made by Lite-On (FCC# H4ICM15006), not one of the other P-B 1512SL chassis (made by Goldstar, etc.). If so, the number of this Zilog is Z0861404PSC-1570 (be sure it is version# 1570). Often, however, that Zilog, if thermal, can be made to function by attaching a (grounded) heatsink to it. The other high-failure chips in that area are I702 (MTV003N) and I703 (Eeprom, Atmel 93C56). The Eeprom is the more common failure, and must be obtained preprogrammed. Try LJ Enterprises (www.ljent.com) or Nationwide (www.neiparts.com) for these chips.

QUESTION NO. P323-9: Acer 7176ie monitor, when switched on, the power comes, led light on and relay clicking but no raster. Checked B+, it is normal. Measured the voltage across HOT, no voltage. Changed many capacitors around hot/fbt, but still symptom.

If there is no B+ to the HOT collector, is the gate of the B+ regulator FET Q303 being driven? If not, do the pair Q301 & Q346, and Q302, operate? Is the initial drive signal emanating from pin 6, of IC304 (TDA4855), or is IC304 being shut down, due to low Vcc (pin 9), or by an Xray-protect input (pin 2), or by taking HPLL2 (pin 31) low? Did those replaced capacitors include C320 (disk cap), and electrolytics C307, C353; as well as the trio C3950, C3951, C3952, and their associated 1 Mohm resistors?

QUESTION NO. P322-4: Techtronic monitor (made by Panasonic/Matsushita) pn 119-5113-00, chassis 21HV4S shuts down after a couple of hours. After shutdown it will not turn back on until it sits at least a half hour, then it will only stay on a minute or two. I was able to wake it up by plugging and unplugging the power cord a few times, but in the process of troubleshooting this way the Horizontal output transistor shorted. I replaced the transistor and the HV diode across the transistor and the original problem was back. I removed the output transistor in an attempt to test for signal on the base drive but the monitor instantly shuts down with the transistor removed. In circuit testing with DVM found no other obvious problems. I'm guessing it's the flyback (pn ETF42L28AZ) and I am in process of trying to locate one. I do not know how to troubleshoot it since it immediately shuts down (power LED off) when the problem occurs. If this sounds like a cap failure how do I find the right one, or should I just start replacing caps. (there's a bunch of them)?

Well, there are some caps known to cause shutdowns in the HV4 chassis. The worst offender is C839, but also C867, which tend to leak fluid out their bottoms onto the board underneath, corroding traces, and conducting high voltages to vulnerable components. Check underneath the caps, clean up all fluid and corrosion, repair any damaged traces and replace any damaged components. C709 & C886 are also known to cause shutdowns if bad, though they may not have leaked to do this. Also, the main board is flimsy, and can get cracks easily. It doesn't take very rough handling to get these, so any cracks may be very fine, needing magnification to see. Jumper any cracked PC runs. A marginal optocoupler PC831 may cause intermittent shutdown on occasion.

QUESTION NO. P222-7: Mag 1795 monitor has no H-drive. Daughter board has +12V feeding it, however pin 18 (VCC) of TDA9103 has only 3 volts. There is a crispy resistor in the position of J709, I need the value.

Another way to find the value of resistor in position j709 is to file a notch in the exact center of resistor burn't , measure from center to one end [the end that measures a resistance ] and multiply value measured by 2. This works in most cases.

QUESTION NO. P320-2: IBM 6555-773 monitor has overdriving G2. It is just raster no video.

Once again, the likely problem in this GDM20E03 chassis is IC420, which controls both the G2 levels and video signals.

QUESTION NO. P320-1: IBM 6555-773 monitor has no video when turned on. I adjusted the brightness button , but nothing happens. However, I can see in the dark the display for brightness is up to 100% already.

The FCC# for this IBM model indicates that it is a Sony GDM20E03 chassis, and it suffers from the same faults as that chassis (listed elsewhere on this page). The common problem is IC420 = CXA1907S (Sony p/n# 8-752-071-56). This IC controls both G2 and RGB video. If pin#22 of IC420 is too low, G2 voltage will be too low. If the fault is low or no filament voltage, check C677 and C683.

QUESTION NO. P37-1: Proview 770 monitor died. No power, no lights, nothing. Fuse is good, cleaned brown glue from flyback area. Has about 150vac on primary of T501 and nothing on secondary. Is this likely the only problem? I need to identify T501 and a source to buy one. Number on Transformer are 730-102-7721 9928 LAE.

For this type of component, contact Proview; they will sell parts, but have a minimum. EMC/Proview, 800-776-8439, X5712, Reggie Rosca, parts dept. Have on hand all relevant information, model#, serial#, date of manufacture, part location and marking, etc.

QUESTION NO. P316-4: Compaq V55 612 monitor is dead, the led does not light. Replaced Q402, still does not work.

The flyback transformer, and IC602, a Samsung KA2S0680 (in the power supply), are known failure components.

QUESTION NO. P36-4: HP d2807a monitor, I need the values of R335 and R601.

I believe this HP is similar to a Viewsonic 17G (Panasonic chassis). In the Viewsonic, R335 = 2.2K, and R601 = 150 ohm/2W. You might check Q305 = 2SA1872.

QUESTION NO. P39-9: Princeton Ultra monitor, had 1" horizontal band in the middle of the screen). Checked and replaced Bu2525af--problem solved. Then after couple of days it would not turn on (led turning on on front panel but dead.) Checked both HOTS and saw that a mosfet in the switching power supply had gone bad but I do not have any part # (k21--). Tried a k2142 but mosfet shorts and has been blowing fuses ever since. Also replaced 3842.

If this Princeton "Ultra" is an Ultra 17+, and if the FET is Q801, then it is a 2SK2141. The 2SK2141 is rated for 600 Volts, while 2SK2142 is only a 250 Volt FET. Also, you might check ZD801 = 12 Volt zener, Q414, & Q416. However, I do not know if this information also pertains to the Princeton Ultra 14, Ultra 15, Ultra 20, Ultra 70, Ultra 75, Ultra 100, etc., if your chassis is one of those, instead.

QUESTION NO. P39-8: Dell D2026ths monitor (crosses to Sony GDM20e03), has no video and no high voltage. The tube does not light up at all but the green light stays on and has good power draw. I had the monitor working once, was letting bench test picture started to flicker then went out. I have not been able to get the video back since.

Try checking for any cracked connections around the flyback on the G board. Also might check C677, C683, and IC603 while there.

QUESTION NO. P39-5: ADI Microscan 5PD monitor, I need a sub for a shorted HOT, part number 2SC5515 made by Panasonic.

2SC5515 is rated 1500V, 17 Amp Ic (27 peak), 65 Watts, Vce[sat] <3V @ 8.5 Amps Ic, Tfall < 0.2 usec. Possible subs for that could be 2SC4891, 2SC5045, and 2SC5411. (Relative to other manufacturers, Panasonic tends to define their maximum currents more generously, given that they test Vce[sat] and DC gain well below that maximum.)

QUESTION NO. P39-4: Princeton monitor FCC Kdsevokd-1730. Changed flyback and Q411 (with originals from Kds), R901, 902, 904. The monitor came on for a few seconds, then the flyback began to squeal and blew Q411 again. The voltages from the power supply are correct.

Since R904 was one of the burnt resistors, IC401 (TDA9103 or STV7778) may also have been damaged by the fault, so check that IC. Also, it is not unheard of, for KDS to provide a replacement flyback for EVOKD-1730, that is defective right out of the box! Other items to check might include Q405, Q407, Q408, Q415, Q416; C437, C438, C447; and IC402. The Princetons also can get bad solder on W404 (also on the FBT, but probably not an issue anymore), and bad yoke connector connections.

QUESTION NO. P39-2: Sun/Sony GDM-20E20 monitor lacks vertical linearity (showing a "S" wave form from top to bottom). Cannot be adjusted on the front panel. The symptom remains stable for every resolution. According to the answers to the Q. P1019-7 & P930-1, I replaced all elect. caps on the DA board, and got no improvement.

The GDM-20E20 is not the same chassis as a GDM-20D10. One common failure in the GDM-20E20, that gives linearity & other problems, has been IC007 = CXA1908S, the DPU on the D board (Sony p/n# 8-752-076-34). This IC is expensive; I'd try to confirm the cause with a board swap from a working unit, before buying it.

QUESTION NO. P39-1: Dell Ultrascan D1626HT monitor shows no signs of life at power-up. The fuse is good and I can trace 120 back to the large rectifier. Even the degauss relay does not pull in during power up.

The SMPS circuit in this chassis is pretty complex. The controller IC used for driving the switching transistor converts feedback for both voltage and current into a real-time power usage factor, via an onboard multiplier function. I suggest getting the service manual (Sony p/n# 9-978-596-02) from Sony, for the related chassis Sony GDM-5001PT, before trying to troubleshoot this Dell's power supply.

QUESTION NO. P37-9: Sun gdm-20e20 (oem by Sony) monitor, I can only see osd picture, but it is very dim (bright and contrast to max).

Is your G2 voltage too low, or is G1 too negative, or is the filament voltage too low? If the problem is low G2 (or G1), the usual problem is a defective IC420 = CXA1907S (Sony p/n# 8-752-071-56), on the CRT board. If the output on pin# 22 is too low (well below 3.4V), this will cause low G2. Be careful to avoid damaging the board, when removing this IC; it is safest to clip all the pins and desolder them individually. If the problem is not the IC420, then check IC407, and then Q403, Q414, and Q417. If the problem is low filament voltage, go to the G board and check/replace C677 & C683, and also check the solder on IC603. If this chassis was handled roughly, there may be cracks on the G board near the flyback, often at the mounting screws, which should be repaired.

QUESTION NO. P37-3: Viewsonic P815-1M monitor comes on but there is no high voltage, the output transistor for the high voltage transformer runs warm. The flyback tested good with the tester.

Check Q861 (11N008) on high voltage board. If it is open, replace it and replace the FBT (TLFA00965). The problem you will encounter is that to adj the focus, you need a special software (provided only to authorized service centers) to do this.

QUESTION NO. P36-8: Daytek DT-1536D monitor keeps blowing the HOT transistor after 20 min from applying power. There is a snap then no screen. All pins of the HOT are shorted.

These Dayteks are known for bad solder on the board. Remove the board and check all over for bad solder. Often, there is bad solder on the connections to the flyback transformer, and that can blow the HOT, so be sure to re-solder those connections. Also check D410, a dual damper/modulation rectifier.

QUESTION NO. P36-1: Sony GDM-20E01T monitor goes into (fault) shutdown within seconds after switching on. The green power LED lights as usual, and then the green and orange LED (standby) slash in sync. The right control panel LED (CENT) is then lit constantly. The HV is there, and the vertical oscillator is working, too (for about a second). Smoke has been reported to come out of the front of the monitor when the fault occurred, but I cannot find traces of it on the board. Even though it should be rather obvious because the oscillators do work, I measured the HOT and the usual suspects, everything seems ok. Any ideas what the meaning of the CENT LED is in this situation, or where to look further?

The CENT LED on solid, with the other two flashing, indicates a scan circuitry failure (usually horizontal, but sometimes vertical). One cause can be bad caps in the power supply, like C610, C611, C612, C615, C616, C617, C619, C625. Also, check Q511, Q512, D504, PS500 & PS501 on the main board. Bad solder, in either the horizontal or vertical circuits, can also cause this fault code.

QUESTION NO. Tatung c7bzr monitor with a wide screen and severely pincushioned.

This is a common fault on this monitor. Replace D434 diode pack which contains the damper and modulation diodes. Goes leaky reverse direction. Will be a DMV-32 but replace with DMV-56.

QUESTION NO. P12-10: Mag DX1795E monitor picture is too wide about 100% and adjusting picture width has no effect. Picture height is ok and is possible to adjust. I found also burned resistor, R503 and I need value of that. Degaussing has no effect.

I found a similar scheme (Mag DX17FE) where R503 is 47 1/4W and one terminal is to ABL (White) and another to diode D501 (1N4148) both in emitter of Q503 (A733).

QUESTION NO. P26-9: KDS VS-19sn monitor. I need the ID of R497.

R497 = 1 ohm fusible. I'd also check out R498, Q407, Q425, D403, D409-D412, D431, and if any are leaky/bad, I would also be suspicious of the flyback transformer.

QUESTION NO. P25-8: Apple 1710 monitor seems that something is missing on this monitor. Two pins, HP8 and HP9, are on the main board. There is nothing connected to them although I believe there should. I think that I could get the set going by placing a bridge over them but...What is the value of resistance RL115 also on the main board?

First, be sure the unit is provided separate H & V sync signals (not composite sync), or a good signal from a PowerMac, or it will not power up. HP8 & HP9 are not meant to be bridged during normal usage. However, you can try bridging HP8 & HP9 for testing IF the unit has no power LED or other sign of life (degauss, etc). You'd get degauss, etc, but not video, because it's bypassing the CPU. If this bridging works, either the solid-state relay is bad, or the CPU did not give it a turn-on signal. RL115 = 27K ohm.

QUESTION NO. P15-8: EMC SA-770 monitor is dead, main fuse ok, HOT appears ok. It blew the top of c635 (22mfd/250v).

If C635 blew, check/replace D632 (ultrafast type, 31DF4 or similar) and FET Q630 (IRF634A or similar). Also check the solder on the three resistors, off the FET source.

EMC is now recommending a chassis modification, to reduce the value of C635 to 10 uF/250V (from 22 uF). Apparently, the original value of C635 was excessive, and overstressed the circuit, causing the failure of the rectifier, cap, and FET. Also, D632 is now recommended to be outright replaced, regardless of how it checks, when C635 has failed; the rectifier can be damaged, yet still test fine on a DMM.

QUESTION NO. P110-8: Likom Technology LTM1502L monitor, I need the value of C112 which was burned and equivalent for Q101-2SK1507.

This monitor equivalent with monitor SAM M152PNLD. C112-100uF/16 and must check Q101-2SK1507 (no equivalent), U101-KA3842, R122-0,33ohm/2W, R123-150ohm, R117-47ohm, R118-10Kohm, R120-47ohm, R121-67ohm and D109-1N4148.

QUESTION NO. Nokia 447X monitor. I need a replacement part number for M3 a driver transformer in the deflection. Number on the transformer is FM2525 5373.

The part number on the small transformer IS the part number. I had the same thing on a FUJITSU-ICL monitor (even SALORA). Try all these brands (monitor may be called 447*).

QUESTION NO. Acer 7076 N monitor starts for a second, the high voltage is passing 30K-volts, and it shuts down. The VARA and VARB from the power-unit is too high, VARA is about 160V dc. I cannot find any defective components in this part of the power unit.

The circuitry design will drive the VAR voltages too high when there are interruptions in the HV or horizontal circuits, and when VREF is incorrect or missing. Check that VREF stays at about 2.5 VDC. Check for bad solder all along the VREF line, and elsewhere; esp. check/reflow the solder on the M605 connector, it is often cracked, and also the yoke connector. For the fault of excess HV, check out IC308 and IC309, as well as any diodes connecting to their pins, and check Q323, R239, and R243.

QUESTION NO. P21-7: Mag DX1795 monitor has no horizontal drive to HOT. Suspect IC 701. Is this the TDA9103 IC I saw mentioned on an earlier post? I cannot tell what the chip number is due to a ground foil glued to the chip.

Yes, IC701 is TDA9103; for confirmation, a TDA9103 is a 42-PSDIP IC package. That metal shield was presumably added for some protection against damage from arcing, which has been suspected to be a failure mode for these IC's. This suspicion is lent some weight by the observation that ST Micro has incorporated an internal metal shield into the design of their STV7778S chip, the latest generation in this series of IC's.

QUESTION NO. P131-5: Gateway 2000 monitor, EV900, Model X19001, No FCC ID has OSD but no video. I replaced the video processor (M52737SP) and the DA converter (IC403, UPD6211CX). If I apply 5V at contrast pin 17 of video processor or pin 5 of the DA converter video comes on and looks good.

Since you still get a good OSD on the display, it is likely that some parameter like sub-brightness, etc., got set too low in Factory Mode. To enter Factory Mode, power up while holding in the selector button on the display. You should now see an "F" on the OSD, to indicate Factory Mode. Check & adjust the parameters, as required.

QUESTION NO. P130-6: Nec Multisync XE15 monitor. I need the value or any information of transistor J306.

"J306" is 2SJ306, a P-channel MOSFET, rated at 250 Volts, 3 Amps, 25 Watts, Rds[on] < 2 ohms. There are not many substitutes, due to the 250V rating; the possibilities include 2SJ306 itself, 2SJ307, 2SJ449, and IRFI9634. Try Dalbani (www.dalbani.com), MCM Electronics (www.mcmelectronics.com), LJ Enterprises (www.ljent.com), or B&D Enterprises (www.bdent.com) for these devices.

QUESTION NO. P112-8: NEC multisync 70 monitor will intermittently not turn on from cold start. The led is amber and there is a constant clicking.

I just fixed one of these - it sure felt like X-ray protect but is apparently a power supply issue. Adjust the SMPS output setting, you will probably find that it has drifted out of spec (there is a pot for the adjustment).

QUESTION NO. P126-10: Magitronic C-SV1700PS monitor, the HOT shorted, also diode D407 (to-220/ 2 lead). I replaced HOT with an ECG 2365 and the diode with a NTE 598 ( I am not sure if these are the correct replacement, since I cannot read the numbers and letters on the original parts). The unit's switching power supply looks to work ok. When turned on, there was a "rattling" sound then stopped, HOT is fine but D407 shorted. Also, what is D407 for?

D407 is DD54RC, a damper diode made by Sanyo, rated 1500 Volts, 5 Amps, Trr <1.5 usec, TO220FI case. B&D Enterprises (www.bdent.com) or LJ (www.ljent.com) may have this one, or an alternative, such as Sanken's FMP-G2FS, and Toshiba's 5THZ47 or 5TUZ47, to name a few. Since NTE 598 is only rated 600 Volts, that is probably why it shorted. The ECG 2365 is not too bad a match for the OEM HOT, but you might also check if all these components shorting, has damaged the in-line microfuse.

QUESTION NO. P122-3: Impression Vienna 17 DX1795E monitor, FCC IAWDX17FG. The brightness was too high with retrace lines visible. I checked the HV and made a few adjustments, the brightness came down, the retrace lines disappeared, but the picture was green and fuzzy. Adjusting the focus improved it somewhat, but before I could check anything else the HOT blew. Does this Mag made unit need the upgrade parts changed, as listed for the regular Mag 1795? (All the part numbers on the CB are different). I suspect the FBT (focus circuit) is bad. Will the FBT for the 1795 replace this one?

Your DX1795e and the Mag DX1795 are both FCC# IAWDX17FG, and should have equivalent components. I think you may be confusing components in the Mag DX17F chassis, which has different circuit components (including the FBT), and also has a host of components that need checking/replacing when it goes down, with those for your DX17FG chassis. Before replacing the flyback, you first might check that the problem is not an internal leakpath within the CRT; for example, a focus-G2 short. The flyback# for the DX17FG is TF2-6V0-001-LA, if the FBT is the problem after all.

QUESTION NO. P119-10: Sony CPD-300SFT monitor, the power to C4833 and R638 burn. Found the power part number VDR687 may be bad. It looks like a capacitor (10V431K and TNR printed on it) but it is not a capacitor. What is it?

TNR-10V431K is a Metal Oxide Varistor (MOV), from UCC or Marcon. It is rated for 275 VAC(rms) continuous, 350 VDC; and surge of 3500/2500 Amps. It should read open-circuit (good or bad) at low voltages, and can only be reliably tested with a current-limited high voltage (1 mA, at 430 Volts +/-10%V). The Panasonic MOV, ERZ-V10D431, is an equivalent, listed by Digikey (www.digikey.com), cat# P7257-ND. Also similar, are MOV's from Mouser (www.mouser.com), 570-V275LA20A (Harris) or 1492-275V14 (Xicon); and from NTE (www.nteinc.com), their MOV's 2V275 or 2V300.

QUESTION NO. P117-10: Polycat monitor of a pick and place, the input automatically switches between the built in 386 computer and ccd camera connected to the loading arm of the machine. The monitor is not turning on. It is a European kit using stv2102, tda8174 ic. Where can I find datasheet of stv2102 or stv2102b (ic was replaced but in vain)?

Go to www.bdent.com/schematics/STV2102.pdf to get the datasheet for STV2102.

QUESTION NO. P117-9: Princeton KD-1511 monitor FCC EVOKD-1511. D806, D816 burned (marked 31DF 6 8L). Could not cross, guessed and replaced w/ generic 3amp/1000PIV rectifiers. HOT shorted. Replaced HOT. When plugged in, power led flashes, D806, 816 get very hot (desolder themselves).

If your "generic" diode substitutes were not ultrafast types, using them to replace ultrafasts like 31FD6 can result in their dissipating excess heat, or even a failure to rectify at all. The 31DF6 rectifiers are ultrafast rectifiers from Nihon Inter, rated 600 Volt, 3 Amp, Trr < 50 nanoseconds. Possible substitutes include Sanken's RL4A, Mospec's SF38, Shindengen's S3L60, Motorola/ON Semi's MUR460, ST Micro's MDV04-600, and Philips' BYV28-600. You can try B&D Enterprises (www.bdent.com) for MUR460, RL4A, and S3L60. Although "HER" type rectifiers frequently do not perform as well as the above types, if nothing else is available, then HER306 might be tried.

QUESTION NO. P117-3: Mitsubishi Diamond Pro 17 TX monitor only has green signal, even on On Screen Display. Using the correct cable. Customer says that originally, only the blue signal was bad and red has gone only recently.

The common cause of color loss is a bad SMD IC, IC201 = AN93B04SCR, a 28-pin flatpack IC on the back of the video board, p/n# CP263P05701. However, due to the expense, check first for loss of color signals occurring at that IC. If IC201 is not the problem, loss of colors can also be caused by bad solder joints along the video path, and sometimes by a failure of IC203 = LH2426S, the video amp, on a heat sink.

QUESTION NO. P112-7: Sony CPD-100GS monitor. Shorted D516 and Q520 IRFI9620G, after replacing with new parts, monitor would turn on with signal cable disconnected, OSD came on but the same parts would short immediately when signal cable is connected to computer.

You might check Q507 & D506 for excess leakiness/short, and see if the solder on the leads is cracked. Also, if the D516 (typ. a Toshiba 3DL41A) was poorly subbed, both D516 & Q520 would blow again. NTE/ECG 588 can be an acceptable sub for 3DL41A, if the original rectifier is not obtainable.

QUESTION NO. P111-5: PC Direct /Smile CA6736SS monitor FCC GBVCA6736SS came in with a shorted red drive. I replaced that and it worked well for a couple of days. Then the chopper transistor in the Power supply blew. The fuse went as well. I replaced the main power supply FET with a 2SK2161. I am not sure of the original as it was blown apart. It seemed to read 2sk214? I also replaced the PWM chip UC3842 and of course the fuse. When powered up again the fuse and trany went. I tested all secondary diodes the HOT, pre driver, all caps and diodes in the powers supply primary, in fact everything in the primary even the main power transformer. All test OK. The unit does not use a PTC which can crack and cause such a fault. All other posts only discuss horizontal faults in these monitors. I have checked all the remarked components anyway.

A 200 Volt FET (like 2SK2161 is) seems a pretty low voltage rating, to use as a replacement for a chopper FET in the primary of a SMPS. If the original FET began with 2SK214x, and had a TO220F case (like 2SK2161), the best candidate for the original FET is probably 2SK2141, rated at 600 Volts and 6 Amps; B&D and MCM's catalogs list 2SK2141. Or you could try an NTE/ECG 2379 (or an IRFBC40) with insulation hardware. Some known failure components in this chassis include D104, D105, Q103, Q105, and R111.

QUESTION NO. P15-1: Samsung SyncMaster 3Ne monitor, the screen is only showing half of the video, and is folded over on top. There is also a very bright white line in the middle of the screen. I checked the RGB cable from the video card to the CDU with a multimeter but it is intact.

Vertical output IC needs replaced, and then check caps.

QUESTION NO. P19-1: Daewoo CMC-1707B monitor. I need a source for a transistor type No FMP-3FU in the UK.

FMP-3FU is not a transistor, it is a dual modulation/damper rectifier, made by Sanken (Allegro). You might inquire from Sanken's UK distributors, listed at http//www.allegromicro.com/salesloc/sal1eur.htm. Also, B&D Enterprises (www.bdent.com), in the US, does ship internationally.

QUESTION NO. P14-6: Micron 700CX monitor stopped retaining digital screen settings after power has been turned off. Once the power has been turned off and turned on again, the user has to readjust the size and position settings, etc. (using the front panel buttons).

Replace the Eeprom on the main board (an 8-pin chip with the number something like 24lc16b). This is the same Eeprom that holds all of the alignment settings also so you will have to reprogram a new one by downloading the stored data in your existing Eeprom to an Eeprom burner and then burn a new Eeprom. Otherwise you will need to get one off of another Micron main board.

QUESTION NO P19-3: Sony (Silicon Graphics) GDM20E21 monitor has a display that appears that the bottom 1/2 of the screen is compressed to 2/3 normal size on one trace then on the next trace the screen appears to be too large. Straight vertical lines seem to also be jagged or skewed left and right. The problem is isolated to the board on the left side of the monitor as you are facing the screen (The board containing the HOT and other video amplifiers.)

I would be suspicious of IC007, the DPU IC on the D board. It is common for this IC to fail, and create deflection problems like these, and sometimes even shutdowns.

QUESTION NO. P19-2: Sony (Silicon Graphics) GDM20E21 monitor has a dim display.

This chassis is related to the Sony 20E03 chassis, and shares some of the same problems. If the problem is bad voltage on the CRT filaments, try checking C677, C683, and IC603, on the 'G' (power supply) Board. If the problem is reduced G2 voltage, or low G1, try checking IC420 = CXA1907S, Sony p/n# 8-752-071-56, on the 'A' (CRT) Board. If the voltage from pin#22 (typ.~3.4V) of IC420 is too low, the G2 voltage be too low.

QUESTION NO. P18-6: HP D2818A monitor manufactured 1996. According to your answer some time ago, this monitor had a weak CRT made by Samsung. Can I swap the HP CRT (M41KUK36x01) with an Apple CRT (M41KKA16x)?

I am dubious of such a substitution. That Samsung CRT is a shadow-mask type, while M41KKA16X is a Sony Trinitron (aperture-grille) type, and has three separate G1 pins, one for each cathode (R/G/B). I would lean towards using a Hitachi CRT/yoke assembly for a replacement. So long as the horizontal and vertical coils have similar inductances to the coils on the Samsung CRT, replacing the entire CRT/yoke assembly will make one's life much easier, in getting acceptable convergence, compared to trying to swap the Samsung's yoke assembly onto a replacement tube.

QUESTION NO. P18-5: AT&T CM1200 monitor FCC A3KM055 (Philips) went to excessive width, which cannot be adjusted with screen controls, pincushion also has no effect. The video is otherwise OK. There are no signs of burnt components or overheated area's of the board.

Try checking the ultrafast rectifier at location 6614, typically a MDV04-600 (could substitute MUR460 or NTE/ECG619), for excess reverse leakage or shorts.

QUESTION NO. P15-6: Apple Multiple-scan nr m4436 monitor with 1705 display, the horizontal adjustment and width (horizontal) pinoculation cannot be adjusted. The vertical adjustment is okay, the whole adjustment is being done by the same console. (no pot meters).

The usual problem is either a defective Q405, or bad solder on Q405, sometimes also causing R448 (390 ohm), located across B-E of Q405, to burn as well. Occasionally, the programmed Eeprom (a 93C46 or similar chip) needs reprogramming/replacing.

QUESTION NO. P1226-9: KDS' Multi-Scan Color Monitor FCC IDEVOKD-1730. The fuse had blown and the connector H403 had burned. The following components were faulty: Q801 - K2333, Q411 - BU2525AF, Q407 - C4368, Q415, Q416 - IRF630, IRF644, IC801 - UC3842, D812 IN4148. I replaced all the components, mostly with equivalents. On switching the monitor on, the fuse is blown. I hope this monitor does not have that KDS design flaw that requires an upgrade. I suspect that the flyback is the cause but I'm not sure and don't know the replacement part number. Also is seems very hard to remove the CRT-base board - how is this achieved (might be glued on)?

The flyback is KFS-61411A, and can be obtained directly from KDS. This chassis is not the one requiring the upgrade; the upgrade is for FCC# EVOKD-1700V.

QUESTION NO. P1227-3: Viewsonic 17 monitor chassis 1782-2 has no vertical height (just displays a line). Is this likely to be the vertical IC? If so, where is the IC located, and should any other components be replaced along with it?

Has this unit been worked on before? If it is a relatively clean unit, check the Connector and Wiring from the Vertical circuit to the Main Yoke. Sometimes at the factory they seat the connector poorly, or do bad crimp jobs.

I believe the vertical IC is IC490, LA7838. You might check it for internal shorts, or for faulty power rails (pins 1, 8, 13); also check for bad solder, and check resistor R499 (1 ohm).

QUESTION NO. P1227-7: Viewsonic 17EA monitor, power LED blinks on then goes off when power is applied. R76 is burned. Nearby transistor Q10 is shorted. Power stays on after removal of Q10 (D1563A). What is the correct value of R76?

The value for R76 is 100 Ohm .25 watt, the color is Brown, Black, Brown, Gold.

QUESTION NO. P1227-4: Digital VRC21-HA monitor. I need the replacement part number for Q341.

Q341is a chip transistor labeled in the schematics as C3338. It is in the BLUE predriver on the video board. The parts list lists Q341 as 2SC3338AR02. The monitor is manufactured for DEC by Mitsubishi. The Mitsubishi model is a THZ8165SKTKW-AE.

QUESTION NO. P1219-8a: Samsung GLsi monitor has lost horizontal scan, the image is squished to 2 inches at the center.

Try checking for a leaky Horizontal Output transistor (MJW16212).

QUESTION NO. P1222-3: CTX VL500 monitor loses Horiz and blanks out if the case is pushed on but is restored when pressure is removed from the case. Removing the case, it is almost impossible to re-create the problem. I found some cracks in the PCB but after fixing these cracks and jumpering all associated tracers, the problem still persists. If the deflection board is bent extremely, it will blank out. I magnified, poked, bent, just about everything and I cannot find it.

Try checking/reflowing the solder off the legs of Q106.

QUESTION NO. P1218-5: Sun GDM-20E20 monitor is too bright, only can see some line on screen. The G2 voltage is 0v, KG\KR\KB voltage all are 10v.

Try checking IC420 and IC405.

QUESTION NO. P121-9: IBM 8513001 monitor. I need values for R806.

Iif R806 is from the power supply then its value is 370 ohms at .25watts.

QUESTION NO. P1211-8: KTX BM15D monitor is missing the plug. The DB-15 pinout for the ground is red, green, blue, red ground, green ground, blue ground. The wire has a grey shielded wire (green, green ground), a red (red, red ground), a blue (blue, blue ground), all those wire are shielded (ground). I have to find ID bit1, ID bit2, ID bit3, Vsync, Hsync. The orther wires I have are black, white, yellow, orange and brown. (not shielded.)

pin 1 red (video), pin 2 grey (video), pin 3 blue (video), pin 4 black (matt), pin 5 black (matt), pin 6 black (video red), pin 7 black (video grey), pin 8 black (video blue), pin 9 n/c, pin 10 black (gloss), pin 11 black (matt), pin 12 brown, pin 13 white, pin 14 yellow, pin 15 orange.

QUESTION NO. P1226-2: Gateway EV700 (YE0711-01) monitor has a blank screen. HV is ok. Problem started intermittantly. Pilot light seems to work ok, even in power savings mode, but screen is now always blank. HOT checked ok. Tried solder reflow of various sections with no luck.

Check voltages off the SMPS. If low try replacing caps like C922 1000mf@16V.

QUESTION NO. P1214-2: Apple M1823 monitor. In reference to questions NO.P817-4, NO.P628-3, and NO.P922-7, I have three M1823 units with identical problems: flashing LED's (power saving and center light on left side of monitor) and no video. The following refers to one of the three units I was able to locate and test all picofuses, R851, R868, D824, and D825. All tested ok. I removed Q512 and tested its hFE with a RMS DMM which shows its value to be 4.85. I am unsure as to the nominal specification of this (hopefully bipolar) transistor because the number printed on its case (C3997 4B4) does not come up in any searches I have done. I also removed Q511 (P-MOSFET # IRFI9630G), but have been unable to verify if it is good or bad as my RMS meter does not handle FET type transistors and I do not know what values to read on which pin during an in-circuit live test. Will a bias test (treating the transistor as if it were two diodes) work on FET's out of circuit? The capacitors C611 and C612 on the power supply physically look ok, but I am unable to read their high capacitance (3300 microFarad) values directly with my limited meter. You also mention checking electrolytic caps for bad ESR leakage. Can that be performed with a standard DMM? My assumption is that the fault is in the horizontal scan circuitry (perhaps Q511 primarily), but I am unsure. I am fairly new to the component level repair of monitors (I used to just board swap) so I appreciate your patience with my novice questions.

First, in using those other answers, you must distinguish between the "central" LED of the five closely-grouped Adjustment Indicator LED's (that LED is actually for Pincushion/Geometry), and the Centering-Adjustment indicator LED (the rightmost of the five indicator LED's). Q512 is a 2SC3997, a Sanyo NPN transistor (pinout BCE), the case markings show only the base number. To test a Power MOSFET with a DMM, first check that there is very high-to-infinite resistance (out-of-circuit) between the gate lead, and either drain or source leads. Then short the gate to the source, and check that there is a good diode junction between drain and source (infinite in one direction, one diode-drop voltage in the reverse direction). This diode will be forward-biased from drain to source on a P-channel FET (like Q511, pinout GDS), and the reverse direction on an N-channel FET. As most FET's fail shorted, this usually is enough. Rarely, a FET fails as nonresponsive to its gate applying a voltage roughly 10VDC (9-volt battery is OK) between gate and source (Source more positive on a P-FET, more negative on an N-FET), will cause the drain-to-source resistance to drop from infinity, to a low value, on a good FET. Testing electrolytic caps for ESR with a DMM can only be done in a cumbersome manner, and only if the DMM has a frequency-response for VAC, that is accurate up to about 10 KHz or higher. If your meter does have that capability, you place a small (1 to 10 ohm) resistor in series with the cap leads, apply a 10 KHz sinewave signal across both, and use the meter to determine the value of the AC voltage which is dropped across that resistor, and then across the capacitor. By assuming the voltage dropped across the capacitor is due to its equivalent-series resistance (ESR), you find the ESR from the formula ESR = (Cap.voltage/Resistor Voltage)•Resistor value. However, good ESR meters are MUCH easier to use, and quite inexpensive, well worth the investment (Anatek, for example, sells the Dick Smith and Cap-Wizard meters, both fine ESR testers).

QUESTION NO. P1212-9: Applevision 1710AV monitor, I need the values for two burnt resistors RL48 and RL52.

RL48 = 470 ohm, and RL52 = 2.7K ohm.

QUESTION NO. P1213-9: Sony GDM-20E03 monitor takes 15-30 minutes to get a picture on the crt. The high voltage is coming up as soon as the monitor is turned on. Also, there is no glow in the tube while there is not a image and the led is solid green. The input has been verified to be good.

The most likely cause would be two marginal or leaky capacitors, C677 = 100uF/25V and C683 = 1000 uF/16V, on the power supply board ("G" board). While there, check for any cracks on the G board that may need jumpering, especially by the FBT, around the two support screws. If there is still a problem, try checking out IC603, and its solder.

QUESTION NO. P1212-1: Mag dx17f monitor. Green light on, no picture, no secondary voltage out of the power supply. Replaced c321, c301, zener diode off r305 mounted on the back of pc board. Voltage on ic 304 is pin 1-0.9volts, pin 2-minus 0.17volts, pin 3-0, pin 4-minus 0.6volts, pin 6-minus 137volts. Q301 measures not shorted. Flyback transistor, q109 is ok.

Is IC304 is functioning, and doubling your 137V across the two big filter caps? If not, check resistors & caps around IC304, check IC304 itself, and diodes D301 through D304. If the voltage is doubled, is there voltage reaching the drain of Q301? If not, check for bad connections, or a bad primary winding, on the transformer. If there is good voltage to the drain of Q301, is R311 good, and is IC301 delivering good pulses to the gate of Q301? If good pulses are reaching Q301's gate, but it is not turning on, perhaps the FET is nonfunctional. If no gate pulses at all, is IC301 getting good start-up and running voltages to pin#7? If insufficient (<16V) startup voltage, check the two 360K tickle resistors. If these are OK, check that IC301's running voltage stays good, & check IC301 itself, and the components around it.

QUESTION NO. P1127-7: CTX 1765CD monitor has only a white/color vertical line in the center of the screen. The hor. deflection should read 58V, but it is 0v. At T304 58v is also missing. Q314 looks ok, as well as D319. I think those should provide that voltage. Q319 measures 0 0 4 V, where I would expect 58, 180, 61V, on T302 and T304 the 58v are also missing.

Besides the Q314, D319, and Q319, try checking D420 and R380.

QUESTION NO. P128-5: Gateway CPD15F13 monitor FCC AK8CPD15SF1 - 1994. The unit shuts down after a certain length of time. Is this because of the keyboard and mouse are not installed? Also the color of the screen is light blue when the brightness is turned up. No adjustments on the crt to set the gray scale.

What you need is a video signal with good H and V sync inputs, to keep this chassis from entering power-save mode, not specifically keyboard/mouse. This chassis is notorious for bad solder and cracks in the main board. Check carefully for cracks, with magnification, and jumper any broken PC traces. Check for bad solder everywhere, but especially in the front center area of the board, and around IC502 & IC504, also the rivets on the heatsink around the flyback, on the horizontal drive transformer, and the HOT & other big transistors. Another cause of shutdown after several minutes is sometimes from overheating of a daughterboard at the front. Regarding the color balance, on this model, it is adjusted by Sony's DAS software program and interface, using the 4-pin in-line header on the main board.

QUESTION NO. P128-7: Viewmaster CA1706 monitor. Both Horz O/P and EHT generator are ok and pulse levels seems ok as well on both base and collectors but I have no EHT whatsoever.

Check c510 & c511. If that does not work, try replacing lcd.

Replace C117 electrolytic capacitor (adjacent to Horz O/P Transformer) it dries up or goes open circuit.

QUESTION NO. P125-1: Proview PV-7221M monitor had ticking sound. I replaced HOT C5150, worked for 24 hours then dead again and HOT shorted out.

2SC5207A or 2SC5251 are probably better choices for Q615, than 2SC5150, for this 17" Proview, but that change may not solve the immediate problem. Try checking/replacing the solder on the horizontal/vertical yoke connector. Also a good idea to resolder generally, but perhaps focus on the area around IC604. Probably also should replace C629, and check that FET Q621 hasn't gone bad in the interim.

QUESTION NO. P1130-4: Acer 7278c monitor has bad pincussion and is narrow.

BSS89-DMOSFET (Case T0-92) location Q301-9 or around flyback outside the heatsink. Have used IRF630 MOSFET, but not quite the screen size, as the original part.

QUESTION NO. P121-8: Sony GDM-20E21 monitor has flyback lines on screen. There is no G2, because the signal from pin 22 of a CXA1907S is low, which is shutting of the G2. I have a +ve 7volts on each of the G1's, and there is no drive on any of the cathodes. Is the Video Pre Amp common to cause this fault ( CXA1907S ). My clamp pulse is sitting on a 0.5v DC level, and the amplitude of the clamp pulses are 6 volts. I am not sure if this is correct.

A defective CXA1907S (Sony p/n# 8-752-071-56) is a common cause of problems with G1 and G2, often resulting in little or no G2 voltage. Besides the video preamp circuitry, CXA1907S contains DAC circuitry, for setting the levels of RGB bias & gain, contrast, G1 & G2 voltage. So it is conceivable it is causing your symptoms. Note that the video output IC, IC405, is also a known failure component in these chassis.

It could be a blown fuse PS001 on the videoboard. Sometimes it blows without any reason.

QUESTION NO. P1121-1: Digiview HR-50 monitor, d703 is shorted (by359x) has no cross. Where can I find this part and is there anything else that needs to be checked?

BY359X-1500 and BY359X-1500S are Philips dampers, rated for 1500 Volts and 10 Amps, in an insulated TO220 case. The 'S' version has a faster reverse recovery time. A regular BY359 might substitute if insulating hardware is added. It may also be possible to substitute Sanken's FMQ-G2FS or FMQ-G2FLS for BY359X; both are 1500V, 10 Amp, in insulated TO220 cases; FMQ-G2FS has the faster reverse-recovery time. B&D Enterprises (www.bdent.com) lists the FMQ-G2FS and FMQ-G2FLS.

QUESTION NO. P1129-9: Medion MD1772e monitor. I need value of R241 and marking for Q301. Where I can buy transformer T302 (marking 19*20079*011 LSE)? I have good signal on base Q301 but signal on collector Q301 is bad. There is no HV Collector Q301 is connect to pin T302. Maybe T302 was shorted.

This chassis is similar to the Acer 76e. In the Acer chassis, R241 = 10K ohm, and Q301 is the horizontal driver, actually a small FET, BSS89 (even though the board is marked B,C,E). With R241 bad, ceramic disk cap C327 = 220pF/2KV should be replaced (3KV is best), no matter what its condition seems to be. Also check R329 = 10K, R328 = 4.7K, R326 = 3.9K; 3 Amp. microfuse J013; D308 = UG4D; ZD210 = 5.1V zener; Q302 HOT (2SC5048); Q316 FET = IRF740 or similar; IC201 = TDA4858. Check the solder on the leads of T302 before trying to replace it, but if a source is needed, maybe try that part number with a Mitsubishi supplier (from a Mitsubishi 1772e).

QUESTION NO. P1122-4: Packard Bell 3010 monitor FCC BEJCM710 has no HV. HOT checks good, LED flashing green/amber. Can verify all voltages in SMPS which cycle as monitor clicks. Have checked many components, but cannot locate the fault.

Possible HOT and/or video logic circuit. Check DC rails out of PSU.

QUESTION NO. P1121-6: Dell 800HS series model d825tm monitor. I need the value of the power switching transistor Q602. The manufacturer number on the transistor is w804. Does ECG have a replacement?

Dell D825TM is a Sony-designed chassis which is equivalent to Sony CPD100GS. Q602 is a Mosfet IRFIBC40G-LF38, Sony P/N 8-729-038-51.

QUESTION NO. P1117-4: Mag DX700T monitor. I need values for R102 and R212.

My notes show R102 = 150 ohms, R212 = 2.2 ohms.

QUESTION NO. P1116-6: Viewsonic 17GA monitor when it powers up, or changes scan rates, it takes sometimes over a minute for the screen to reach full brightness. It slowly comes up, from a black raster. The only other side effect, is a little ghosting to the right if high contrast edges.

Try checking capacitors C212 and C215 on the CRT board.

QUESTION NO. P1115-8: View Sonic P810 monitor powers up (no HV), shows low resolution boot up screen then shuts down upon resolution change when windows starts after POST. No raster or anything after shut down just yellow stand-by light. Cannot determine if the problem is Low Voltage section of a HV regulator and HO transistor problem.

This Panasonic chassis has a couple of common problems. The PC board is flimsy, permitting cracks to occur, especially near transformers and big heatsinks. Use magnification to check for these. Also, the electrolytic caps are common to leak fluid, that corrodes PC traces and causes mischief. Any fluid must be cleaned off, and traces repaired. You might check if C852 has leaked, possibly shorting D602. If D602 shorted, check for other damaged components, like C601, R602, R919, Q902, etc, as this would send damaging voltages into the HV protection circuitry.

QUESTION NO. P1114-9: Unbranded OEM version of the 17" KDS EVOKD-1730 monitor FCC EVOKD-1730. On cold startup picture is about 1" high but as unit warms up picture expands, finally being about 70% full size (full size top scan and about 50% bottom scan). Have checked solder joints to no avail.

I would begin at the vertical IC for your OEM chassis. It may be IC301 = TDA8172. Besides the IC itself, check the supply rails (pins 2 & 6 on a TDA8172) for proper voltages during startup. Also check for any leaky electrolytics off these rails, as well as off the output (pin 5) and on the return from the vertical yoke.

QUESTION NO. P1114-6: Dell D1528-LS monitor FCC H4ICM15006. I need the value and sub for Q803 which is blown, only partial ID is possible ?507. Also the original R814 looked to be too small to be 25 watt, should it not be 0.25 watt?

Sounds like Q803 is Fuji's FET 2SK1507, rated 600 Volt, 9 Amp, 50 Watts. Try B&D (www.bdent.com), Dalbani (www.dalbani.com), MCM (www.mcmelectronics.com), etc. for that FET.

Q803 is type K1507 and R814 =1 kohm/0,25 W.

QUESTION NO. P1115-2: Peacock Entrada 17" Monitor. I require the equivalent of diode D113 which has only the marking 31DQ 06 8A as I have one which is short circuit. I tried all the normal sources of cross-reference but no success. There is another of the same type on the PCB and it reads 265 ohms.

31DQ06 is a 3 Amp, 60 Volt Schottky rectifier made by IRF; General Semiconductors' SB360, Vishay's SR306, or Rectron's SR360 might also substitute for it. Digikey (www.digikey.com) lists 31DQ06 and SR306. Mouser (www.mouser.com) lists the SB360 and SR360. An NTE/ECG 579 might also substitute, but would be pricier.

QUESTION NO. P1114-1: Acer 7177is monitor. I need a sub for hot transistor 2sc5048. I tried 2sc4747 n and 2sc5148 but it damaged the hot always. The fbt transformer is okay and tested.

2SC5048 is a 1500 Volt, 12 Amp, 50 Watt HOT. Possible subs include 2SC4890, 2SC5105, 2SC5124, but 2SC5048 itself is often cheaper, and available from places like B&D Enterprises (www.bdent.com), Dalbani (www.dalbani.com), and MCM (www.mcmelectronics.com). Before going further, have you carefully checked or replaced electrolytic caps C307, C353, C3950/51/52, the ceramic disk cap off the collector of Q306, and checked IC201 and FET's Q303 & Q314? Defective components might be causing the HOT short out. Also, D308 may become leaky, when Q306 was shorted.

QUESTION NO. P1114-3: AST RMO7F11 monitor FCC GWGRMO-RTO7FXX, the picture appears on the tube, but it is horizontally squished to only fill about half the screen. Obviously, the digital adjustments do not fix it.

Try checking the 15 Volt zener ZD301, and Q302. If either is bad, check C350 and digital transistor Q350. Also, it is wise to desolder the bottom lead of heatsinked damper D303, and check that its lead extends all the way through the board. If it does not, add an extension wire before resoldering it.

QUESTION NO. P1113-6: AST Vision7L monitor FCC GWGRMO-RTO7FXX. Q346 and Q350 burned, C350 and C343 were popped - need to id Q346, 350 - marked as R1001 504 - unable to cross.

Those transistors are Samsung's KSR1001, digital switches with two 4.7K resistors built into the base connection. An NTE/ECG 2355 might substitute; other possible substitutes include AA1L3M, DTC143ES, RN1001, & UN4222. B&D (www.bdent.com) and MCM (www.mcmelectronics.com) list the DTC143ES.

QUESTION NO. P1019-1: Samtron SC-428PSL monitor with width reduced approx 3 inches both sides. No width control or pincushion control. Checked main semi's no success.

Check Q406 for broken solder connections, also change D407. May test ok but change anyway.

QUESTION NO. P119-5: Acer 1768i monitor. Changed Q306 (BU2525AF) and C3950, C3951, C3952 (no capacity). A month later Q306 blown again. Found C307 without capacity. Is this the cause?

C307 affects the base drive for Q306, so if C307 is bad, it can cause Q306 to fail. Besides C307 and the three 450V capacitors you mentioned, also check C353, and always check the 2KV ceramic disk cap off the collector of Q306, these are common failures. When those three 450V caps go, you should also test the megohm resistors paralleled with them as well.

QUESTION NO. P117-4: Sony cpd 1604s monitor. Related Questions P610-4 and P1011-10. On initial power up (one second or less) green power led comes on and crt face has characteristic HV "feel", then it all shuts down. Actually, the SMPS is still on but is being crow-bared by Q901/NEC5p4m/scr. Isolating the gate on this device allows the +165vdc to come up, and the green power led remains on. It seems Q901 is likely doing its job.

I believe the gate of Q901 is fed by pin 10 of IC401. Check the LM324 op amp on that IC, and perhaps also check D406 and R434 & R435 from the FBT high voltage shutdown circuit. If these are all good, perhaps the HV is truly excessive. I think it should be about 27.5 KV with a B+ of around 68 VDC in VGA mode.

QUESTION NO. P116-4: LG studioworks 44m, 14 inch color monitor is fine when switched on but after a use of app. one hour the image gets blurred and the brightness level increases considerably. All voltages at the CRT remain unaltered ie. the same as when switched on but the pin at screen grid rises from 242 volts to 310 volts positive. It seems that this problem is caused by the increase in screen focus and may be final anode voltages at the CRT. However all the SMPS voltages and the voltage at FB output transistor collector plus the control grid voltage of -100 volts remain stable. Is it the FBT that is faulty?

With no model number provided, one cannot be specific, but certain Goldstar 14" chassis are known for getting bad FBT's with such symptoms.

QUESTION NO. P118-5: Packard Bell 3010 monitor, FCC BEJCM710. I need a value and source for component L701. Only markings are 150-235K WS. Should be an inductor, but no mh ratings.

That FCC# corresponds to Goldstar Chassis# CA-42, same as a Studioworks 74i, so try LG Electronics (formerly Goldstar), or a Goldstar distributor, such as Astro or Shine Electronics, for that chassis's L701 part number.

QUESTION NO. P116-6: Three Dell D828FI monitors (seems to be similar as Samsung 550??) with same problem. While warming up, picture becomes distorted in vertical direction. Vertical vibrations appears too. Top 1/2 of picture is expanded and bottom 1/2 of one is pressed. Freeze spray has no affect around IC TDA9302H.

The fault symptoms suggests that the TDA9109 needs replacement. This i/c provides hori/vert etc processing.

QUESTION NO. P116-9: IBM 2124 -001 monitor, manuf. date dec.97, it has a Samsung CRT (mod# M36KUQ35X92) (SKD). The part # of the main PCB is 55.78520.001. I need the value of C335 on the main PCB or any useful info in identifying or cross referencing (the cap is burnt beyond recognition).

This chassis is similar to the Acer 7154e. C335 is a 220 pF/2KV ceramic disk capacitor, but is better replaced with a 3KV rating. Mouser (www.mouser.com) carries such caps.

QUESTION NO. P1010-9: Samsung Sync Master 17GLsi monitor. I need the capacitance and voltage values of C429 and C430. They are both connected to the HOT.

I believe that I have the same monitor as in question, basic model no. CMH 7379L SyncMaster GLsi, main board model CMH 73*9 rev. 2.01. The C429 on my board reads "252J2500V BUP 509" which means 25 x 100pF J = +/-5% tolerance 2500V. The C430 "202J 1600V BUP-S" = 20 x 100pF J = +/-5% tolerance 1600V. Don't know what the other letters/numbers mean,could be some temp. range. Apparently 100.000 pF = 1uF. I am just a layman in this so the following info was based upon the following resources http//www.xtronics.com/Kits/ccode.htm and http//www.ee.washington.edu/circuit_archive/capacitors.html. Other useful info are at http//www.us-epanorama.net/main.html.

QUESTION NO. P1030-10: Samsung CQA4147 monitor turns on OK, but only shows a horizontal line on the screen.

Try checking the vertical IC, R301, and R307.

QUESTION NO. P1030-7: HP D2818A monitor FCC A3LCMG737. There was an interrupted "funny" resistor R508 (looks like a fuse?). I need the value and cause. I replaced it by resistor 1 ohm. Everything was O.K. but after repowering-up Q502 and Q503 have gone.

R508 is a 1 Amp, 125V Fuse. Sometimes Q502 just arcs through its insulation, and takes out that fuse, and maybe also the B+ regulator. But you might also check Q416, the FBT, and the CRT for shorts.

QUESTION NO. P1027-10: IBM 6544-403 monitor has raster but no video. However, when powering down video is momentarily present. Replaced LM1205 on CRT pcb-same.

On this G70 model, when there is no video with the signal cable still attached, but the picture flashes on the screen during shut-off, the usual cause is a bad rubberized-membrane control panel (under the CRT face), which must be replaced.

QUESTION NO. P105-8: Ampro 1100 video projector manufactured by Zenith. Ampro is no longer in business so I would need to know the Zenith model number for this projector to get a service manual from Zenith, it was manufactured in 1993. When turned on, it powers up, and after a second or two the high voltage shuts down, the Conv/HV SMPS voltage is 145.

Check the FCC ID CODE located on the the back of the unit (on the same sticker as the model) where the first 3 digits identify the manufacturer and the remaining digits identify the model, then visit www.fcc.gov/oet/fccid/ to locate contact the OEM, Zenith 1-800-243-0000 (Alabama)

QUESTION NO. P1027-4: CTX VL700 monitor. Need value of R341 (source resistor of Q311) burnt beyond recognition.

R341 is a 47k quarter watt.

QUESTION NO. P1026-4: Gateway 2000 CS1572DG monitor. Need replacement/cross for D509 (has FUF4004 on it).

FUF4004 is a 400 Volt, 1 Amp, ultrafast rectifier. General Semi's UF4004 or IRF's 11DF4 are replacements. Mouser Electronics (800-346-6873; www.mouser.com) lists UF4004. Other possible substitutes are HER105, SF16, and NTE/ECG 574.

QUESTION NO. P1023-10: KDS KD-7300 monitor, FCC EVOKD-1730. The screen cracked a few times, then went dead. LED flashing and power supply clicking. Checked for burned components and diodes, OK. Found HOT (Q411) shorted, replaced. Powered unit back up, HOT shorted again. Saw a brief puff of smoke, didn't last long enough to see location...nothing looks burned.

Check for bad solder on the flyback, W404, and yoke connector, and for bad crimp connections in the yoke connector plug, that may contribute to failure. The flybacks in this FCC# are common to fail in the ABL winding, and burn one or more of resistors R901-R904, sometimes also shorting IC401. Also, with your symptoms, you might check Q406, C438, C447, C455, D402, D407, D411, and L401.

QUESTION NO. P1024-3: Relisys RE767B monitor is dead. Replaced shorted HOT (Q504). Unit now functions but T501 runs hot and shows signs of previous overheating, i.e. puddle of brown goo at base, which appears to have melted from interior.

If T501 is marked 7351170016303 CHI 9819, or similarly, Nationwide Electronics (888-634-7278; www.neiparts.net) has been able to special-order this coil before.

QUESTION NO. P106-10: Apple colorsync M3705 monitor displays half screen verticle when connected to computer, but internal signal, controls etc. display ok.

Check connector of H-deflection yoke for bad solder joints. In that case, QL-23 is also bad (replace!). Replace RL163 (even if it measures ok!!). Another cause is a bad capacitor CL-9. Most of the time one pin is burnt. In that case, replace the capacitor and also the above QL23 abd RL163. If this does not solve your problem, check if the collector of TL23 is about 50-60V dc. If not, check QL2. We had two cases with the same problem caused by a shortcircuit between QL3 and the heatsink (replace the siliconrubber).

QUESTION NO. P1024-10: Gateway yeo711 monitor. I need the value of D112and R115, keep blowing horizonal outputs.

D112 is IRF's 11DQ06, a 60V, 1.1A Schottky rectifier; R115 = 0.18 ohms.

QUESTION NO. P1023-5: We have (8) NCD CM3800 monitors FCC A3KM053 with no video.

Two common problems seen with FCC# A3KM053, are bad R573, a 1 ohm resistor by the yoke connector on the main board, and bad flybacks.

QUESTION NO. P1020-5: Imagic 778L monitor. I need the value of R634 and the cause of it burning.

R634 = 3.3K, 1/4 Watt. A bad flyback is the common cause for burning this resistor. Also check the HOT Q521 = BUH1015HI, and R633 = 12K ohm.

QUESTION NO. P1020-3: Acer 716ie monitor with pincushion distortion. Pincushion control still works but cannot adjust enough. Replaced C3950-3952, C353, C320 (100pF, 2KV), with no improvement.

If this is actually an Acer 7176ie, try checking Q312, Q313, and D308 for excess reverse leakiness.

QUESTION NO. P1019-9: ProVista PD-959 monitor, FCC IDBR8PD-959. First no H.V. Q563(2SK10069, Q831 (BU2520DF) was shorted and R866 (2,2ohm) was burned. I replaced, when turned on Q563, Q831 and R866 there and then damaged. There is no signal on B-Q831 and G-Q563 but signal on S-Q830 (BSN254A) is o.k. Signal for horizontal output is 800Vpp and always work good.

Try replacement of the flyback transformer T806, LZ250A000P, Sampo FEA662, when those components repeatedly die.

QUESTION NO. P1018-6: Acer 54e monitor with c335 burned (blinking led and no picture). Should I replace c335, r214, d316, d317 and q317 (info from other questions)and if so what are the values of d316 & d317?

Replace C335, when it is burnt. Mouser (800-346-6873; www.mouser.com) is one source for the 220 pF/3KV disk capacitors, as well as the ultrafast UF5404 (D317). Components other than C335 only need to be replaced if they are burnt, off-value, shorted or open. Sometimes the diodes and the FET aren't totally shorted, but have high leakage in the reverse direction. If R214 is bad, consider that IC201 = TDA4858 may also need to be replaced, and if Q317 (IRFI630 or 2SK2161) is shorted/leaky, also check coil L304. And don't forget to check out Q310 = BU2525A.

QUESTION NO. P102-10: Voxon MO-D1428 monitor FCC LFVDX-1448. I need the value of r825.

R825 is 0,47 Ohm resistor Yellow Violet Silver Gold. If burned again the flyback is short and you are out of luck. Supplier is out of bussines and no way to get it so far.

QUESTION NO. P929-5: Daytek (Daewoo) DT-1536 monitor with no vertical sweep, only a bright line across the middle of the screen from left to right.

Poor solder connections on the vertical ic causes this problem. Replace the ic and check associated caps. Also resolder the flyback pins.

QUESTION NO. P1010-5: Dell D1528-LS monitor, R814 in the power supply is smoked. I need the value of it, plus, are any other components in that area likely to need replacement?

Value for R814 is 1kohm 25watt. Check to make sure R801, R810 are not open. Check if Q803 or I801 shorted.

QUESTION NO. P1013-9: ICL 17C, type447H monitor, FCC IEY447H and Olivetti CDU1782MS monitor have equivalent main boards. On main board three resistors were burned R205, R120 and R198 (may be R195 or R196, I can`t see good). I need the values.

R120 = 100 ohms; R195 and R205 are both 215 ohms/0.5 Watt. It might also be a good idea to check R224 = 0.47 ohm; P-channel FET's like T13 and T27; and inductor M3.

QUESTION NO. P921-2: IBM 6324 monitor has burned resistor R321causing it to appear dead when a video signal is applied. Need the value of the resistor, and possible causes why it may have burned. There is a 47 mf 50v cap attached to one lead - tested good. The resistor is located near Philips IC TDA4852 that I have been unable to cross.

R321 is 100 ohms. Check if zener CR310 is defective, or if vertical IC Z302 = TDA8351 is shorted; or if the supply voltage to pin#6 of Z302 exceeds 50V. The TDA4852 is a Philips Horizontal & Vertical Deflection Controller IC.

QUESTION NO. P106-3: Monex monitor (the FCC ID calls up Shin Ho Electronics from Korea), has poor EW correction adjustment (I have three with the same problem). The EW adjustment works a little on some resolutions and does not work at all on other. The H size can be adjusted but it's still to big on lowest setting. Checked EW correction signal from TDA 4858 and through the amplifier stage and it looks OK. I found one of the switching FET's damaged. Replaced with no improvment.

Without your providing the model number for the monitor, or even the full FCC number, I cannot know if this will apply to yours, but IF this Monex is a SM585 type, a common cause of pincushion in that chassis, is capacitor C225 = 4.7 uF/50V.

QUESTION NO. P104-2: Dell 1528-LS monitor, with burned resistor (R468). I need the value.

The value is 21ohm 0.5W +/- 5%.

QUESTION NO. P105-4: Smile 17" monitor with blown HOT (2SC5300). I need a source or sub in UK.

A possible substitute for 2SC5300 is 2SC-5294, or (if the case will fit), 2SC-5142. Try Nikko Electronics, located in Surrey (0208-336-0566; www.dalbani.co.uk) for these.

QUESTION NO. P104-3: Dell V1728E monitor that starts jumping/scrolling after warm up. Changed all caps in vertical stage, still the same. When certain caps and IC(TDA9102C) are sprayed with freeze(just a two second burst) jumping stops. I suspect IC but not sure.

A defective TDA9102C IC can indeed exhibit a vertical-jumping symptom when warm.

QUESTION NO. P102-7: Sony GDM-17SE1T monitor has no raster, the green "Power LED" and amber "Power Saving" LED are flashing simultaneously and the "Geom" LED is lighting. It is not possible to switch off this display. The power supply is ok.

First check IC801 = 4049 logic chip, and microfuse PS500 = SOC1600 (1.6 Amp). If these are not the problem, then check if the flyback transformer is defective.

QUESTION NO. P102-1: Acerview 11D 7133D monitor FCC JVP7133D. I need a cross or sub for D307-1 (T3TH).

This marking "T 3TH" is for a Toshiba 3TH41 damper diode, rated 1500 Volts, 3 Amps, Trr < 1.5 usec. A Philips BY228 or Sanken RH4F might substitute; try B&D Enterprises (800-458-6053; www.bdent.com), Dalbani Corp.(800-325-2264; www.dalbani.com), or MCM Electronics (800-543-4330; www.mcmelectronics.com) as possible sources for these.

QUESTION NO. P103-3: Acer 7176ie equivalent (Elonex MN044) monitor with intermittent shutdown. The vertical output from IC304 stops as does the drive for B+ (drops to about 60 volts) to the high voltage transformer hence the unit stops displaying. The horiz drive continues to be produced. I replaced IC304 (TDA4855) and the fault remains. I do not think it is in X-Ray protection as it still faults with pin 2 of IC304 shorted to GND.

Check the ceramic disk cap off the HOT collector, C320 = 100 or 120 pF/3KV, and electrolytics C3950, C3951, C3952 = 2.2 uF/450V, & C353 = 10 uF/450V. Also check the three megohm resistors in parallel with C3950-C3952.

QUESTION NO. P929-4: Mag DX17F monitor. Found Q301 blown, D319 and ZD301 shorted hopefully nothing else was damaged? I cross reference Q301 and D319 and have replaced them, but I need the value of zener diode ZD301. Also does the chip normally fail when Q301 blows?

ZD301 is an 18 Volt zener. If by "the chip", you mean IC301 = 3842 IC, then, yes, it is good practice to replace this IC when both the zener and the FET have blown. You probably should also check the power fuse, R310 = 10K and R311 = 0.22 ohm, and test all electrolytics nearby for high ESR or leakiness, including C301, C302, & C321.

QUESTION NO. P927-9: Acer 5256 monitor has blown Q333. The only marking I can still read is "630". What is the full marking or what equivelent can be used?

If the transistor is in TO-220 case, is almost sure IRF630 (N FET).

QUESTION NO. P830-10: Gateway 2000 CS151572ES. The HOT (2SC4747) was short. I replaced with 2SC4924, it is not working properly and heating picture is short horizontally.

Check 2SC4924 = SI-N 800V 10A 70W and 2SC4747 = SI-N 1500V 10A 50W 0.3us.

QUESTION NO. P926-2: Hitachi CM500U monitor. Need replacement part number for 110Mhz RGB video amplifier system with On Sreen Display (OSD) LM 1282n.

For LM1282N, try LJ Enterprises (800-627-8755) or Dalbani Corp. (800-325-2264).

QUESTION NO. P926-4: CTX board No. 11531-0310 Rev C1 has two diodes soldered to the bottom. I know that one of the diodes is a 1N4004 but the other one disappeared. Looks like they go from R404 to R429. I need to know what the other one is and why they blew.

That other diode is a 12 volt zener, with its anode connecting to R429.

QUESTION NO. P926-5: I need cross reference for a transistor BSS89 for an Acer 7276e monitor.

BSS89 crosses to the Philips BSN254 or Zetex ZVN4424C, high-voltage, logic-level FET's. However, LJ Enterprises (800-627-8755; www.ljent.com) may have the original BSS89 device.

QUESTION NO. P925-7: Acer View 7276e monitor. R241 was burned. I changed R241 = 10K ohms.C327 = 220 pF/2KV,Q301 = FET BSS89, R329 = 10K, and 3 Amp picofuse J013. Now the monitor seems to be work but it displays 2/3 of the screen vertically on the right and rest of 1/3 of the right side image displays on the left side.

First, check there is still continuity in the path going through R241, to pin #1 of the TDA4858 IC. If yes, then probably the TDA4858 itself needs replacing. Also check that ZD210 = 5.1 volt zener, is not leaky/shorted/missing; it is intended to protect pin #1 of that IC.

QUESTION NO. P922-10: Dell 1528 LS monitor (lite-on FCC H4ICM15006). The red color does nit work. I replaced Q901 and Q902 (2sc2851 and 2sc3611). With an osciloscope I can see that the red, green and blue signals going in I501 (MM1203) have the same level. The outgoing signal of red is about 10 times smaller then the signals for blue and green. I can't find a manufactorer or a datasheet of the MM1203. The IC tell's me it is made by Mitsumi but on their site they do not know it.

The datasheet for Mitsumi's MM1203 is at www.mitsumi.co.jp/Catalog/ic/visual/mm/1203/text01e.pdf MM1203 is similar to LM1203AN (or LM1203BN), and you should be able to sub one of those parts for it. B&D Enterprises (800-458-6053; www.bdent.com) lists LM1203AN. A plain LM1203N is slower than MM1203, and may not be a suitable substitute for it. You might also check the components off pins 5, 26, and 27, as these inputs will affect the red output channel (pin 25) as well.

QUESTION NO. P922-5: Acer 7176is Monitor FCC JVP7176is was worked on by another shop. The symptoms are narrow picture, and shuts down soon after power-up. I replaced the usual C3950, 51, 52, caps with no improvement, other than it does not shut down now. After inspecting this unit for the third time, I noticed Q 314 is missing. I need the part type and # and if possible the orientation.

My notes show Q314 as IRF740. Orientation is not noted, but pin#1 is the gate, which should be easy to distinguish from the others. You might also check out ZD307 = 7.5V zener, ZD308 = 5.6V zener, D326 = 1N4148, all nearby Q314, and D308 = FES8JT.

QUESTION NO. P925-5: Hitachi CM620U monitor, FCC ID IQX96C1769. It loses horiz deflection intermittently. It collapses to a line and back to a full display every couple of seconds when it is first turned on then it might play good for a couple of hours.

The fix was C426 in the horiz circuit.

QUESTION NO. P921-7: Gem DB-770 BA (FCC ID H79DB-770) monitor with DB-1765 cct board has no LED indication, or power out of LVPS or HVPS. Monitor was on STBY during electrical storm although powered through surge surpressor which is still functioning as are all other equipment in house. I have checked most LVPS semi-conductors - which appear O.K.

Try checking R122, R127 = 120K, and R137 = 300K (may be two 150K in series) in the power supply.

R122, R127 were O.K., however R137 was actually 2 x 750K (1.5M) and were O.K. Whilst in the area I noticed that the copper side of the board was darker then surounding ares (heat). So I checked some related components on spec and discovered R124 470K, it was an open cct. Replaced the component, the unit is now serviceable. The only concern I have is why the difference in R137, I am assuming that the value has come from a Cct diagram?

QUESTION NO. P919-1: Apple Multiple Scan 20 (M1823 montor, two led's flashing center on solid, no HV. Replaced/checked common failure parts including c611/612 in PS. I need part number for d504, 824, 825 and flyback. A source for flyback would be helpful also.

D504 is a 13 Volt zener; D824 is a 1SS119 signal diode, but a 1N4148 can substitute. The flyback is 8-598-929-00, but can be replaced by the currently-available Sony p/n# 1-453-162-11; which a Sony distributor, for example Fulton Radio Supply or Andrews Electronics, could supply. It is for the Sony GDM-20SE1, the Sony type of this Apple.

QUESTION NO. P918-4: Sony GDM-20E20 monitor is lacking brightness. Checked G2, has 122v G1 OK, cathode OK, filament OK, voltage coming in is 850v. I believe this is OK. I have no manual as I do not repair many of these monitors in Oz.

The most common cause for G2 problems in this model is a defective IC420 = Sony CXA1907S, Sony p/n# 8-752-071-56. To remove the old chip, amputate all pins and remove them one by one, or you will likely damage this board.

QUESTION NO. P918-2: Acer 1772e monitor. I need values for R241, C327 and R329.

In the US, this Acer chassis is the Acer 7276e. R241 & R329 are both 10K ohms, and C327 = 220 pF/2KV (a 3 KV replacement is better). It is also wise to check R326, R328, FET Q301 = BSS89, HOT Q302 = 2SC5048, ZD201 = 5.1V, IC201 = TDA4858, and 3 Amp microfuse J013 whenever C327 fails.

QUESTION NO. P915-9: I am trying to replace the CRT (broken neck) in a Mag DX1795 monitor. I have an Identical tube number from a dead DX17F that is slightly older. he yolks and adjacent field canceling coils are similar but not identical. The DX1795 yolk contains 3 adjustment pots whereas the DX17F yolk does not. The connectors are also not identical but could probably be rewired. Should I keep the yolk/tube combination intact and rewire or should I transfer the yolk to the good tube? I am really hesitant to go this route as resetting the purity and convergence would probably be a nightmare which I may never be able to get right.

My suggestion is to keep the yoke/tube combination intact. You may measure first the electrical resistance (the inductance could be great) of the H yoke and the V yoke. Usually, the H yokes are about same resistance (0.5 ohms) but you must be very careful because his reactance could be very different (it depends from frequency). About V yokes, if the resistance (usually 10 ohms) is approximately identical (+/- 20%), is ok. You just may readjust the vertical size, which is easy. If the resistance of the V yokes is very different, you have no choice, you will need to transfer the yoke and remake the geometrical, purity and convergence corrections, which indeed, it is not easy, but not impossible! Try placing the original correction magnets in same locations like on the old tube.

If the two horizontal yokes have about the same inductances (probably near 135 uH), I'd keep the DX17F yoke on its own CRT. I agree that swapping yokes will be a convergence nightmare. You can change quite a few parameters in Factory Mode on a DX1795, and could go back later to swapping yokes, if the DX17F yoke won't work.

QUESTION NO. P97-1: Gateway 2000 ev900 model X19001 monitor. First no H.V. Replaced FBT now got H.V. Cannot adjust a proper focus. Picture sharp on the middle of screen, but on the left and right along the vertical still blur (dynamic focus not function.). When adjust horz. size effect only a little and also effect the height and brightness. Is Q117 mosfet FS10SM16A? Someone replaced it before me.

Q117 is a Mitsubishi FS10SM-16A. You can find the datasheet at http//www.mitsubishichips.com/data/datasheets/power/pdfs/20000430.pdf Also Q112 is a Toshiba 2SC5142.

QUESTION NO. P913-7: Compaq persario V410 304 monitor. I need easy replacement D413 #DMV32A and which type of this component.

DMV32 is a 6 Amp. dual damper/modulation rectifier from ST Microelectronics. The pinout is #1 = K(damper), #2 =A(damper)/K(modulator), #3 = A(modulator). The only 'easy' replacement (other than DMV32 itself) would be another ST Microelectronics dual device, DMV56, although a Sanken FMP-2FUR might substitute. Not as easy, because the device is larger, and so might require a modification to fit, would be Sanken's FMP-3FU or FMQ-3GU, carried by B&D Enterprises (800-458-6053; www.bdent.com).

QUESTION NO. P912-4: Compaq v70 monitor, the video will expand and contract horizontally. I replaced the vertical processor and related caps, also found a blown 2.7 ohm resistor in this circuit. I checked other caps as well to no avail.

Be sure to check common-failure capacitor C851 = 47uF/250V, located between the center of the board & the flyback; it can sometimes be leaky, instead of bad ESR.

QUESTION NO. P810-2: Packard Bell 3010 monitor FCC H4ICM17008 has no display, LED is on (orange). The HOT seems okay.

The problem was very simple, but not obvious at first. Another technician worked on it before me and he stressed the yoke connector that cracked the traces without being visible. I only resoldered the yoke connector.

QUESTION NO. P96-8: Dell (Sony) d1526t-hs monitor. When started a click is heard, then the power and the power save light begin to blink, simultaneously. No hv, but B+ is approx 30 v and the other voltages also very low. Checked that the power supply works, but apparently in a standby mode. When power switch is pressed the green light gets steady but soon reverts to blinking. Replaced the HOT, which was shorted. The low voltage to operate the smps is 6 v but should be at least 8,5 v. Checked all the diodes, caps. What makes the unit adopt a standby mode?

This is a Sony 15SF1 chassis. These go into a shutdown mode when the circuitry detects faults, so there are numerous reasons why yours may have gone down. Most common are cracks in the board traces, and bad solder, particularly towards the board center, and around the big heatsink, and including the solder on heatsink rivets. Since the HOT was shorted, other components to check include FET Q503, C599 = 22 uF/100V, D504, Schottky D508. Also check if the N board is regulating the Horiz. drive transformer voltage properly; pin#1 of T504 should be about 60 VDC in 640x480 mode.

QUESTION NO. P96-7: Princeton E017 monitor was dead to start with. We replaced shorted D411 and got the picture back up. Now there is a pincushion problem and adjustments make no difference.

Check L402 (a good one should ring well, be about 8.2 mH inductance, and about 18 ohms DC on an ohmmeter), and check or replace IC401 = STV7778 or TDA9103. This assumes nearby electrolytics and diodes (D409, D410, etc) checked out OK.

If pincushion and horizontal size did not work, the transistor that is after horizontal yoke (usually in TO 220 case) is broken. Voltage collector is depending to horizontal size, about 40V.

QUESTION NO. P96-6: Gateway DX17S monitor is out of focus. If the focus controls are turned up it starts snapping in the crt socket. I need help trying to locate it TLF063-01-39 flyback.

You are having trouble locating the flyback, because that number you are using denotes the focus divider. This flyback should be TF2-6V5-001-LA. Try Mag Innovision, since they made this chassis.

QUESTION NO. P95-2: Three Optiquest 1769DC monitors with same problem: Replacement HOT shorted after two days usage.

Check for bad solder and cracks, especially at the horizontal driver transistor and transformer, and check the ESR of any electrolytics in the drive circuit. Also, if there is any of that notorious glue on the horizontal or high voltage components or heatsinks, scrape it away; that glue has sometimes caused the HOT to overheat and short.

Upon removing the horizontal driver transistor found the goo that had overheated around the Horizontal Transistor. It was impossible to read the part number.

QUESTION NO. P815-1: Daytek DT-1926D monitor displays only a quarter of the screen in dos and of resolution 640*480, 800*600 ok (image complete). I changed ic301 TDA8351 (vertical) with no results.

In a different model from Daytek it was a little capacitor from 104 in front of chassis C 254 around IC 203.

Q804 is causing the problem. Q804=c3198.

QUESTION NO. P88-7: Sony CPD-200sx monitor. Everything displayed in white is now pink. Other colors look ok. Can any chroma adjustments be made to resolve this problem?

If an external adjustment (for R, G, B) is not available or you cannot obtain a proper color using it, you will find inside six adjustable resistors (usually on the neck board, just follow the signal cable which come from computer). Three of them (sometime only two) are in the near RGB video-amplifier system and they are for amplitude control (gain adjust) and the other three are for bias cathodes voltage. First, you must adjust bias voltage: put on your screen a black image (i.e. DOS background) and adjust brightness in order to see it a little. Now, from bias adjust resistors make background in gray color. Then, put a white image on monitor screen (i.e. open Explorer in Windows) and from gain adjust make window white area in white color (if only two adjustment resistors exist, is a little bit hardly). Done.

QUESTION NO. P830-4: Mag DX1795E monitor has no vertical sync. Responds to OSD adjustments for vertical size and position. Appears to be slightly dim as well.

One cause of this can be a bad IC701 = TDA9103 or STV7778. Try replacing this IC, and be sure 12V regulator IC202 is providing correct output voltage. If IC701 is not the problem, try replacing the Eeprom, IC703.

QUESTION NO. P84-5: ViewSonic 17EA Model 1765EA monitor has a buzzing sound when I turn it on (I believe it is from the FBT) and the picture vertically shrinks and is not clear.

Buzzing sound could be associated with cracks in the solder joints on the Flyback Transformer. Ring cracks are sometimes hard to find unless you look at them with a 10x magnifier. However since you hear a buzzing sound, you may find black arc marks in the solder joints around the leads of the flyback transformer or other components. Do not rule out the possibility that the sound may be coming from some other area. Best defense is to tear it down so the whole board is exposed and resolder anything that even seems questionable. This may prevent having to go into it again later. Do not forget to do the picture tube board too.

QUESTION NO. P822-1: CTX 2085 monitor has dark screen. I need a datasheet for IC sc87c51cgn40 intel 1980.

This is a version of the 87C51 8-bit microcontroller, so try Philips' datasheet at: www.semiconductors.com/acrobat/datasheets/80C51_87C51_80C31_5.pdf. However, for this symptom on this chassis, I would first check C454 = 10uF/250V, near the FBT, which can be accessed from the hole under the PC board without chassis disassembly.

QUESTION NO. P821-9: Sony CPD-15SF monitor. One or two color(s) is missing in picture and in on-screen menu. IC LM1207 is OK.

Assuming it is really Sony CPD-15SF1, check transistors Q102, Q202, Q302 = 2SCSC3955 on the CRT board. If these are OK, check out the data input cable going into the CRT board.

QUESTION NO. P821-8: Mag DX1795 monitor. I need a cross or sub for defective Q301 (K2485).

The part is 2SK2485 and is obtainable from B&D Enterprises 800-458-6053.

First, B&D Enterprises (800-458-6053; www.bdent.com) lists your original 2SK2485. But if that is insufficient, 2SK2485 is a 900 Volt, 6 Amp, 100 Watt, N-channel MOSFET, with Rds[on] < 2.8 ohms at 3 Amps Id. An NTE2377 might substitute those specifications.

QUESTION NO. P821-6: IBM 7097-593 monitor Sept '96. Q607 shorted (Nec J449). I need replacement part # or Equivalent ECG number.

2SJ449 is a 250 Volt, P-channel MOSFET, and it has no ECG replacement. Use either the original 2SJ449, or else use 2SJ307. B&D Enterprises (800-458-6053; www.bdent.com) lists these two P-FET's, but if you cannot get either, an IRFI9630 might squeak by. However, since that one is only rated for 200 Volts, it is not a recommended substitute. Also, check out HOT Q602, R182 = 10 ohm/2W, and just replace C182 = 10 uF/250V.

QUESTION NO. P821-2: Gateway2000 ev700, model YE0711-01 monitor, FCC IDIAWYE0711. Need the value of ZD301.

ZD301 is an 18 volt zener diode.

QUESTION NO. P818-1: Gateway 2000 ev500 monitor FCC bejcs592 shuts down, and after a while it can be turned back on and works fine. I have gone down to the level of taking out componets and testing them individually and have yet to find the culprit.

Try checking IC901, R909, R910, D903, C918, and generally checking/replacing the electrolytic caps in the power supply. Also, look carefully for any bad solder in the power supply and horizontal section. Might also check the 358-type dual opamp near the flyback.

QUESTION NO. P816-8: NEC Multisync 70 7701 monitor (Dec98). High Voltage shuts down after extended periods of use. If it is shut off for a few seconds and turned back on, you can hear the HV come up then shut down again. If power is shut off for about 10 minutes it comes back up and runs for another extended period.

You might try heat & freeze, to see if the Weltrend IC (has markings like WT60Pxxxx) has become heat-sensitive. If yes, try glueing on a (grounded) copper plate to it for a heatsink. If not the IC, check/resolder the main board for (intermittent) bad solder joints.

QUESTION NO. P815-9: Magnavox CM4015 monitor has no picture. Green power led is on. Monitor hums (normal) as power is applied. Filaments are glowing in rear of CRT.

Desolder pins 1 and 5 on the flyback, and check for a high-resistance leakage between these pins. If there is such a leakage, the flyback is defective. Ringing it will not discover this fault. If the flyback tests fine, check the G1 and G2 voltages.

QUESTION NO. P810-9: Packard Bell 2020 monitor. The transistor Q102 (IRF630) becomes very hot after a few minutes and then damaged.

First, Packard Bell has sold 2020 versions made by different manufacturers! If yours is made by GVC (FCC# DK42020), look off the drain of Q102 for a coil, and see if that coil got cooked, has shorted turns (rings bad), or lost much inductance (it's about 4 mH). If so, try replacing or rewinding it. If the coil is good, check any rectifiers or capacitors on the same circuit, and check that Q102 is getting good gate drive pulses from the 3842 IC.

QUESTION NO. P83-5: Sony CPD-1604S monitor has no picture, unit makes humming noise. Horizontal output ok.

Try checking/replacing capacitor C911 = 10 uF, in the power supply.

QUESTION NO. P82-5: Intergraph TX2151W monitor Chassis 21HV4S FCC ACJ93312118, has no blue color displayed, red & green are ok. CRT & solder connections to CRT main socket board check ok. Video cord was subbed out with several good cords.

First, check if the On-Screen Display has any blue showing. If blue is present there, then the color gain data for the blue in the Eeprom has probably been set to zero, and the Eeprom data is corrupted. See if a blue signal is present, going into IC1301 = M52326SP. If the blue signal is there at IC1301, and blue is also missing from the OSD, the usual failure is IC1302 = Panasonic RGB driver IC, VEY09P. Often, IC1302 shorts at one of its color inputs, making the previous IC (IC1301) appear to have a bad output. If VEY09P is needed, try LJ Enterprises (800-627-8755; www.ljent.com) or Nationwide (www.neiparts.net); this IC might also be available from Viewsonic or a Panasonic distributor.

QUESTION NO. P724-2: Sony 17in 200gs monitor. The picture tube takes 3-4 minutes to come up to full brightness. However, full brightness is about 1/3 of a new monitor. All other aspects, ie focus, work with no problems.

Either the crt is worn out or its filament voltage is too low. The filament voltage should probably be 6,3 or 12,6 V. In modern monitors, the filament is usually fed with DC, hence no measurement problems. However, in some cases it is fed with an ac impulse voltage from an auxiliary winding on the FBT (or smps transformer). In this case, you need either a good dmm with true rms capability (i.e. the old Fluke 8060), or a digital oscilloscope which can perform rms calculation on the signal, to get a useful reading. Remember to check the filament voltage at different horizontal frequencies! It should remain within +- 5 % of the nominal value.

QUESTION NO. P728-4: ViewSonic 1786PS monitor. Replaced shorted Q550 ( Horizontal Voltage Transistor C5270A) and it is short again. I checked all other transistors and diodes they are OK.

Often when Q550 shorts repeatedly, the P-FET regulator (2SJ306 or 2SJ307) has also shorted or is leaky, so check for this. Viewsonic's boards are also known for getting fine hairline cracks; these can affect the voltage regulation circuitry for the B+. If, after checking or replacing the regulator FET, it still applies excess voltage to the HOT, try checking the PC traces with high magnification, or checking the continuity of the PC traces with a meter, looking for hairline cracks.

QUESTION NO. P728-2: Dell D1728D-LS monitor powers up, no high voltage. Checked the HOT and Diode (D405) along side the flyback cage and they check out fine. Flyback appears fine.

Check if R508 is open. Check Q416 and Q502. Once in awhile, the insulation coating on Q502 has arced through, and transistor is bad even if it tests good, so check for this too.

QUESTION NO. P726-8: Kuo Feng CA6013DS monitor, FCC ID GBVCA6013DS. LEDs working, but no picture. Found two pins at Q119 shorted. Q119 is a SEC 1RFS640. Also found R134 melted, reads around 5 Ohms. Removed R119 and R134. Picture appears, but is much too wide. What is 1RFS640? Are there substitutes for it? What is the value of R134?

Samsung's IRFS640 is an N-channel MOSFET, rated at 200 Volt, 9.7 Amp, 40 Watt, TO220F. This FET may be substituted by an IRFI640 or a plain IRF640 with insulation hardware, 2SK2135, or NTE2944.

QUESTION NO. P726-5: Proview PV-772IM monitor will not come up. Low ticking sound. Checked fuse on main board & is good. No picture or on light.

Did you check the HOT, Q615? Besides the HOT, check FET Q621, and check/replace cap C629 = 22uF/250V/105�, it's usually high ESR or dead. This chassis is also known to get this dead/ticking symptom due to that brown conductive glue, in the power supply area and in the flyback area, affecting the circuitry. Scrape away any such glue you find.

QUESTION NO. P726-7: IBM 2124 monitor had a blown Q310. After replacing, the monitor and the HV came on long enough for me to see R214 fry. I traced this to a bad c335 and replaced both. I could not find a 2KV cap, so I used a 6KV. Now the monitor powers up, but no HV even after replacing d316 (d317 was OK).

If R214 has fried, it seems likely that the overvoltage also damaged IC201 = TDA4858, so check or replace that IC. Also check out regulator FET Q317, and see if coil L304 looks burnt, rings bad, or has dropped below 0.5 mH inductance (nominally "2 mH", but an inductance of at least 0.7 mH probably is OK). For C335, a source for these 2KV and 3KV (preferred) 220 pF ceramic caps is Mouser Electronics (800-346-6873; www.mouser.com). If there are width/pin problems after power-up, but L304 is OK, then check out Q302 and Q303.

QUESTION NO. P725-2: Gateway Vivitron 17 cpd-17f23 monitor powers up then powers down with both leds blinking. Power supply seems ok. Hot is ok.

Those two LED's blinking is just a general indicator that the monitor has shut down due to some fault it detected. With no other information provided (like any other LED's on?), the only suggestions would be to check some common failure items (besides that HOT), such as FET's Q503 and Q510, ultrafast rectifier D510, signal diode D596 (near flyback, develops reverse leakiness); any open fusible resistors off the secondary, problem caps like C525, C540, C541, & C592; and check for any hairline cracks in the PC board.

QUESTION NO. P721-2: Necesito Remplazo del Transistor A1837para Monitor Goldstar.

A1837 = Transistor 2SA1837, Mouser Electronics (800-346-6873; www.mouser.com; e-mail sales@mouser.com; FAX 817-483-6899, referencia 620-2SA1837); y B&D Enterprises (800-458-6053; www.bdent.com), y MCM Electronics (800-543-4330; www.mcmelectronics.com).

QUESTION NO. P77-6: Hitachi 801HR monitor. We have a number of these which have dimmed over time, and none of the internal adjusts seem to have an affect on brightness, etc.

If the monitors use Samsung or Samtron tubes, they are most likely bad. This is very common. The monitor might last 1-2 years if you are lucky. If it lasts 3 or more years by a lottery ticket, you will win ):

QUESTION NO. P721-4: Dell Ultrascan 21FS-BEN monitor July 1994 manufacture, no cable supplied. Looks like oo::::o. Need part number/supplier.

This cable should not be hard to find, it is used on many monitors ie Nanao and IBM (IBM cable has these nubers on it. FUJIKURA-T part#96g2156 e.c. # 003021B).

QUESTION NO. P629-5: Samsung Syncmaster 15GLi monitor. There is a fried resistor adjacent to what looks like line drive transistor Q503 (C5148). The designation looks as if it may have fried with it and the value is impossible to read. I need the value and cause for frying.

The resistor is R521 a 2.1 ohm 2 watt.

What usually goes when Q503 shorts is R507 1.8ohm 2W resistor and Q505 IRF740.

QUESTION NO. P67-1: Compaq V70 621 monitor FCC ID A3LCGL777. Had contrast problem. Now suffering from a loud ~50Hz buzz coming from yoke. When placing the monitor face down (on tube) to probe the mainboard, the noise dissapears. All rails check OK.

Use plastic cable tyes, combine several togeather and wrap tightly around the frame of the deflection yoke. Tighten untill noise stops.

QUESTION NO. P65-2: Dell d825tm ultrascan 800 series monitor the display is very dim. Fault is not with crt or lopt.

The cap that filters the filament voltage in the switch mode power supply is bad c632 I think that is the correct location very smal 470 uf cap next to a 1000 uf cap in the switch mode.

QUESTION NO. P628-5: Magavox 20CM64 monitor, no power but there is a ticking sound from supply. Removed load from 170v power side, monitor power led turns on.

Check filter caps in the power supply for high ESR. Replace high values.

QUESTION NO. P629-7: Tatung TM6714 Inteliscan monitor, power horizontal deflection transistor 2SC4288A damaged. Base attack is OK, C-E diode OK, C-E condenser OK. When replaced, it burns out in 1 second. What is the problem? Cannot find crosses for 2SC4288A.

Test deflection yoke and high voltage transformer. Also check for drive signal on the base of the horz output transistor.

First, be sure your replacement 2SC4288A was not a generic copy, some of these have been inferior in quality. If the 2SC4288A was genuine, see if the B+ regulator FET Q501 is shorted or leaky, and providing excess B+ voltage to TR402 = 2SC4288A. Are TR101 and TR102 also OK? 2SC4288A might cross to 2SC3995 or 2SC3996; B&D Enterprises (800-458-6053; www.bdent.com) lists all three transistors.

QUESTION NO. P66-1: Goldstar 1453AUTO monitor. I need to identify IC 601 and HOT (Q706).

If Chassis CA-19, Q706 - 2SC4744, IC601 - TDA1675A.

QUESTION NO. P614-10: Gateway 2000, Vivitron1572, Sony cpd15GF13 monitor, runs normally for 20 minutes then the left edge starts to break up (erratic tearing), then it went to a vertical white line down the center of the screen for a split second before going to safe mode (yellow & green lights). The period of normal operation continued to shortened after each turn on even if I waited until the next day. Now it does not come on at all, just the the yellow and green lights at turn on.

The original problem may well have been from bad solder; these chassis are notorious for bad solder joints. Check everywhere on the main and CRT boards, but for this symptom, especially check/resolder the rivets on the heatsink around the flyback, the components situated around this heatsink, and all connectors. Occasionally these boards also get cracks, so there may be hairline fractures in some PC traces. Since the chassis is now not firing up at all, having persisted in running it with this problem may have caused deflection circuitry components to die, as well, so you might also check HOT Q507, P-FET Q503, D504, Schottky D508, and related components.

QUESTION NO. P61-7: Samsung 15gle cma5377l monitor. I need the value of r698 in the power supply.

R698 = 22ohm/1W

QUESTION NO. P511-5: AOC 7VLR monitor, need to identify HOT.

The original HOT is the 2sc50498.

The hot is actually 2sc5048.

QUESTION NO. P67-5: Apple Multiple Scan M4502 monitor Noryber FCC ID BEJC5766 has a prooblem with horizontal sync. Replaced some IC's with a good monitor, no change.

Did you try exchanging the programmed Eeprom, an 8-pin IC, either 93C46 or 93C56? If a new programmed Eeprom is needed, they are programmed while the unit is running, using the Goldstar service manual (usually Goldstar chassis CA-24-6) and a programming jig. A Goldstar service depot might perform this service, if given the Apple M4502 scan rates. You can get the details at webpage til.info.apple.com/techinfo.nsf/artnum/n18615 on Apple's site.

QUESTION NO. P58-10: NEC JC-1531VMA-3N monitor. Q510 is shorted. Installed is 2SJ306. I have seen publications listing this as a IRF9610 and/or IRF9620. What should it really be?

I would stay with the original if possible. This part is available from most part suppliers.

QUESTION NO. P531-5: Korea data system EVOKD-1450G monitor, all controls are working properly, picture ok but intermittent unstable shakey. I cleaned HV cap, changed hor IC GL1151(LA7851) and measured esr of most electrolytics near ic and flyback.

Check the front panel control pots in this chassis, such as horizontal size/phase/width. These are of poor quality, and tend to get flakey; at which point, they need to be replaced. Did you do a solder check on the deflection circuits and yoke connectors?

QUESTION NO. P51-9: A growing number of Acer 76ie monitors we purchased for repair/resale have a thin vertical wavy line appearing about three inches from the left side.

Replace C315 1UF 100V, C3925 2.2 UF 450V, C3951 2.2 UF 450V, C3950 2.2 UF 450V, C353 10 UF 450V, C 607 100UF 50V.

QUESTION NO. P525-6: ProView 768M monitor has a short in damper diode D604. C604 checks good. After installing a new D604 (DMV56) monitor powers up but does not adjust horizontal size from panel. The size is too big.

See if there is a leaky Darlington transistor Q301 = TIP122, in the horizontal area.

QUESTION NO. P524-10: Gateway 2000 cpd-15F13 monitor. I need a sub for D504 which is marked GI 9516 and/or FE 3D. Also I found resistor R 078 chipped (it is near a pc mounting screw). What was the value and type of this part?

D504 is a General Semiconductor type FE3D. This superfast rectifier is rated for 200 Volts, 3 Amps (125 Amp surge), Trr < 35 nanosecond. Subs would include the superfast type SF34, listed by Mouser (800-346-6873; www.mouser.com), among others, or to ECG/NTE 588.

QUESTION NO. P524-1: KDS VS195 monitor does not light, I have any current which arrives on my Hot.

First confirm that there is still infinite resistance between the flyback transformer pin marked "FB" on the board, and the HV anode. There is an internal capacitor that can go bad, then giving a measurable resistance. These flybacks, p/n# Y265387, are reasonable cost from KDS. Check the 1 ohm B+ line resistors R497 and R498, the MOSFET Q407, the HOT Q425, the ultrafast rectifier D409 (a Shindengen S2L60, 600 Volt, 1.5 Amp, Trr < 50 nanosecond), and IC401 = UC3842.

QUESTION NO. P424-6: Samsung Syncmaster 3 CQA41471 monitor. I need the value of L401.

L401 10uh horz. lin. coil part number BH27-20006A.

QUESTION NO. P55-8: Samsung CSQ4387L monitor. Front panel controls cannot adjust the screen correctly. The screen is pulled in at the sides and distorted on the top.

Try checking ic605 for bad solder. This is the 5V regulator and supplies the CPU.

QUESTION NO. P519-8: Several Samsung 3ne monitors with no pin-amp and no horizontal width control at all. Replaced Electrolytics in Horiz. Size amp, tried KSE-800 and IRF740's. No effect. Am I missing a B+ voltage somewhere?

Check Q406 for broken solder connections. Repair then replace D407 UF5404. Very common problem with this unit.

QUESTION NO. P522-7: Sony CPD200ES monitor has no high voltage because there is no pulse coming from pin 19 on ic801. Replaced this ic and the oscilator cap on pin 4 pin 7 says that it should have 12 volts. I only have 9 volts, I believe this is because the power supply regulates off of the 150 horizontal b+. The 150 is right on as well as the 80 volts. The 16 is at 9 and I believe the -10 is at -7.

First try checking R659 = 390 K, 0.1 Watt, 1%; C534, C610; and Q507. Sometimes uProcessor IC901 is faulty. Other known failure items include C582 = 1000 pF/2KV cap (near HOT); D504, D505; D903 = HSS82 (sub is BAV21); FET's Q503 & Q602; and IC904 = TDA9105.

QUESTION NO. P519-10: Gateway 2000 cpd-15F13 monitor, scc-HO1C-A. While hot probing near its base I slipped and shorted Q507a Toshiba 2SC5129, which I replaced hoping that was the extent of the problem. At subsequent turn on it sounded like it tried to come on but no luck, within a second it switched to a yellow and red light mode then quickly to just plain clicking. I was looking for cracked solder joints and caused more trouble for the unit under test. By the way the 2SC5129 is gone again.

Sounds like your shorted Q507 may have also killed the P-channel FET Q503, either an IRFI9630 or an 2SJ307. Also check diodes D504, and D508 (a Schottky).

QUESTION NO. P518-4: Packard Bell 1512SL monitor. I replaced the program chip that controls the select functions for monitor adjustments because the monitor was doing intermittent things and I was unable to change the selection of functions in the front. When doing so, I powered up but forgot to connect the grounds and heard a static pop. The selection problem is cured, but I now have no horizontal sync.

Sounds like one of three chips got zapped; I703 (Eeprom), I702 (Myson frequency select chip), or I701 (Zilog micro). Try the preprogrammed Eeprom first, then the others, for this symptom. Places like LJ Enterprises (800-627-8755; www.ljent.com), Nationwide (888-634-7278; www.neiparts.net), or CCS (800-356-1227; www.ccs-sales.com) may carry these preprogrammed chips. Be sure to get the proper version number for your chassis. It is a good idea to attach a metal strip, or a piece of copper PCB board material, to the Zilog chip, and then ground this strip, to help protect the IC from arcing.

QUESTION NO. P518-8: CTX 2085, 20" Multiscan monitor, made in 1995. Came in with green LED on, no HV and no video. Found shorted HOT - Q314, C3996 but nothing else. FETs check good, FBT rings good. After installing a new C3996, same symptoms, but HOT does not short again.

Check Q313 2SK553, R380 1R/0.25W fuseable, power supply connection wires and HF transformer output pin soldering in powersupply.

I have since solved the problem. Found R380, 1 ohm, 1/2W flame proof (open, but not burned, located on the input to Q319, 2SK553). After replacement OK!

QUESTION NO. P517-4: Mag DX17F monitor. I have changed all the usual components and L105 as last. Monitor is working but it is slightly out of focus. I tried the flyback adjustment with no success.

First, check the inside of the CRT socket, and see if it is carbonized or burnt within the compartment. If that is OK, try rejuvenating the CRT. It is also possible there is a bad focus block on the flyback.

QUESTION NO. P516-8: NEC Multisync 5D JC-2002VMA monitor. I need to identify and a sub for Q5T0A, marked NEC K1271.

2SK1271 is rated 1400 Volts, 5 Amp, 150 Watt, Rds[on] < 4 ohm @ 3 Amps, MP-88 case. 2SK1271 is listed by B&D Enterprises (800-458-6053; www.bdent.com); MCM Electronics (800-543-4330; www.mcmelectronics.com); and Union Electronics (800-648-6657; ued.net/index.html); getting the original is probably cheaper than the other suitable FET's.

QUESTION NO. P515-10: Nec 2051 mh monitor. I need the equivalent of stk 730-080.

The NTE equivalents for the STK730-series only cover the lower-power STK730-010 and STK730-020 devices (110 Watt, 145 Watt). No NTE equivalent is listed for the 210 Watt STK730-080 device. However, B&D Enterprises (800-458-6053; www.bdent.com), Union Electronics (800-648-6657; http//ued.net/index.html), and MCM (800-543-4330; www.mcmelectronics.com) do list the STK730-080 device itself, and B&D also has the datasheet on-line.

QUESTION NO. P512-3: Acerview 76e monitor has a bad C327 (220pf 2 2kv), not only did R241 and R329 go but also R326 and R328 burnt up. I need the values of R326 and R328.

R326 = 3.9K, R328 = 4.7K, both 1/8 watt.

QUESTION NO. P511-7: Acer-7276e 17" monitor. R328, R32? (this resistor is connected at J174/R328 to GND, part of label on PCB is damaged by fire) and C326 are burned beyond recognition.

I do not have a chassis in front of me, but the common failure involves HOT Q302, FET Q301 = BSS89, R326 = 3.9K, R328 = 4.7K, R329 = 10K, R241 = 10K, C327 = 220 pF/3KV, and J013 = 3 Amp microfuse. So possibly your unknown resistor is R326 or R329. See if you can locate both those two resistors intact, or if one is your burnt one (missing).

QUESTION NO. P510-5: Concerning question P728-9 on a VTC SC-7 monitor (Archive Monitor page), does anyone know the root cause of the resistors burning? I suspect the zener diode, but have no way of testing it.

These resistors in the ABL circuit burn, because the flyback transformer is faulty. If your FCC# is EVOKD-1730, then several models from Princeton and KDS (such as the Princeton E070 or KDS VS-7 models) use the same chassis. So replacement flybacks can be obtained from these companies, if finding a source other than VTC is an issue.

QUESTION NO. P418-5: AOC 5En monitor starts up after replacing shorted Q403 (2sc5296) by BU2508DF but runs hot quickly and blew it after fifteen minutes. D408 (3legs) was ok. What semiconductor is this? B+ pin 2 of flyback is 125V without signal. I tried one more BU2508DF but after a couple of minutes monitor was dead. HOT survived. I checked D408 again, now two legs measured short.

Transistor 2SC5296 crosses to NTE2324. A more suitable substitution would be BU2508AF not BU2508DF which has a built in damper diode. 2SC5296 is available from MCM for $2 or $3.

QUESTION NO. P58-4: Wyse WY-15E+ monitor FCC ID LXMWY-1575PES, shorted HOT. I replaced the HOT with an exact replacement (BU2520). The monitor powers up and appears to run normally in all modes with no picture distortion, but if left on over a period of time the HOT becomes excessively, well, hot, and the picture starts to collapse.

Try checking/replacing caps in the base driver circuit, like C226 = 10 uF/100V.

QUESTION NO. P52-4: Digiview HR-50 monitor. I need the part number for Q706. It is burned and the only numbers left are the last two(9a).

My notes show Q706 as a 2SB649A.

QUESTION NO. P55-5: Optiquest V775 monitor with a raster only about 2 inches wide. The raster is not trapezoidal or distorted & video is present. I checked all caps on the main board with an ESR meter & they seem O.K. I replaced the H.O.T., no change.

I would think "Eeprom".

QUESTION NO. P52-3: NEC jc2002vma monitor. Q560(hpa150) shorts repeatedly. Cannot find any other problems.

There are a couple versions of this NEC, so these location numbers may not be exact. Replace the B+ regulator FET, probably a 2SK758 (location Q5P0 or Q5G6), on a heatsink at the front of the main board. Replace capacitor C541 = 100 uF, and check D561 & D562; an older board might have a single D560 installed in place of both D561 & D562.

QUESTION NO. P426-8: Tektronics tx-d1734r monitor, p/n 119-5426-00 17hv7 chassis. Dead screen, LED is lit, no b+ voltage. Replaced k1917 mosfet (shorted). No signs of any other component failure.

Look for an open 3.5 Amp microfuse on the board (F888 ?). Check components between Q675 and the HOT collector, especially any coils for evidence or shorted turns or reduced inductance, and any fast-recovery rectifiers for leakiness.

QUESTION NO. P426-6: EIZO 20" flexscan monitor. In the deflection circuit a blown mosfet (2SK1736 from SANYO) causes a power down. I need a sub or source.

2SK1736 is rated 100V, 1 Amp, 1 Watt, Rds[on] < 0.95 ohm @0.5A, logic level gate, pinout SDG. Possible subs might be IRLU110 or 2SK2201, inserted backwards to match the pinout, or IRL510, if a TO-220 can be made to fit. Digikey Sales (800-344-4539; www.digikey.com) lists the 2SK2201 and IRL510 FETs.

QUESTION NO. P425-3: IBM 2124 monitor. Front indicator flashes about three times per second. Black/blank screen. Ticking sound from transformer in front of Q602 coincides with front led flashing. Replaced Q602 and IC601, checked diodes on P.S. area. Still same.

Check FET Q317 (IRFI630 or similar) for leaky/shorted; also check D316 and D317. If the FET is bad, also check if coil L304 got cooked, and check if it still retains at least 0.5 mH of inductance (0.8 to 2 mH is nominal), or else your new FET may also die. Also check HOT Q310, disk cap C335 = 220 pF/2KV, and R214 = 15K ohm. A bad C335 can cause any of these components to die, so replace C335 if you have even the slightest suspicion; it can test good when it is not.

QUESTION NO. P420-8: Daytek Dt 1730 monitor powers up fine, but with a single horizontal line across screen only.

Check/replace IC401 = TDA8172, Q922 = 2SA968 or 2SA940, C404, and D924.

QUESTION NO. P330-3: KDS KD-1700 monitor comes on for 3-4 seconds then shuts down. No raster appears on screen. The power supply seems to load down. The high voltage is there for as long as the power supply runs. It is hard to tell if the power supply is shutting down the high voltage or vice versa.

KDS will not work with Trident 9580's they will blank out.

QUESTION NO. P419-8: Sony GDM-2039 monitor. How do I adjust other parameters such as pincushion? How do I store it so that when I go back to user mode the adjustments are still there? It seems to revert back to default settings.

There should be a vertical-standing N board, by the flyback, for the relevant circuitry. There are several Sony N board versions, but you should either find the adjusts on that board itself, or you have to set switch SW1 to the Service position, then do the adjusts with the front panel buttons, turn off, and set SW1 back to the User position. The N boards are also a common site for faults that give geometry problems, usually from bad/leaking SMD caps, or bad IC's. For testing components on this board, check the caps and PC traces with power off, or try affecting the IC's using a heatgun. Beware of killing this board from arcing, if you should try to move it around while under power.

QUESTION NO. P417-1: MAG DX-1795 monitor. Brightness and contrast turned all the way down but raster is still visible with a slight green color. Otherwise picture OK. -12, +32, +5, +12 voltages on daughterboard connector are OK.

See if the color bias (or any other) settings in the factory mode menu have been altered accidentally. Power up while holding in both the up & down keys. Open the OSD menu, and there should be a V1 or such, at the side, to indicate factory mode. Use the keys to go to the various selections, use Enter to make a selection, use the up & down keys to adjust the level, then power down to save the setting.

QUESTION NO. P417-9: Gateway 2000 crystal scan 15 model DX15FG monitor with insufficient width/pin cushion. After replacing shorted C106 6800pf 630V mylar only one inch from bottom of screen is not wide enough. D107, Q111, Q206, D103, D104, D128, C103, C105, C124 and most electro caps in power supply and horizontal circuit ok.

Did you also try adjusting the trapezoid, or did you only adjust the pincushion? Press the function select button until no LED except the power LED is on. Now try using the adjust buttons to adjust the trapezoid. If this is no help, check the TDA9103 IC.

QUESTION NO. P418-6: Need to identify hot in AOC 7vlr and Acer 7156-S monitors.

In the Acer 7156S, Q302 = BU2520AF.

QUESTION NO. P410-1: Compaq Presario MV700 324U monitor FCC bjm7ct, no HV. I need the type and value of c607.

Electrolytic 10uf @ 100v.

QUESTION NO. P414-2: Tatung TM3401monitor. I need the value of R808, R805 and D821.

R805 - 56K, 3W R808 - 0R33, 1W (safety) D821 - TICP106D (thyristor)

QUESTION NO. P414-7: Tatung TM6714 monitor does not switch from stand-by and power source does not work. Found Q804 (marked K858) damaged. I need information on it.

This sounds like it would be Toshiba's FET 2SK858, rated 600 Volt, 2 Amp, 40 Watt, Rds[on] < 4 ohms, in a TO220 case. Possible crosses for that FET include IRFBC30, STP3NA60, and NTE or ECG 2379, available from sources like Mouser Electronics, Digikey Sales, or MCM.

QUESTION NO. P412-2: Gateway 500-069cs monitor when turned on goes into shutdown due to excessive hi- voltage (near 30kv). Checked B+@ output transistor (185.0v). Output transistor good, horiz pulse within limits on base of same. I checked all components in the collector circuit.

Check the power supply stage. The voltage should be around 110-120V, hence the trouble. Check the control circuit in the PSU stage. Check 1/2.2/10 micro capacitors in this stage.

QUESTION NO. P413-8: Apple Multiple Scan 20 Display M1823 monitor powers up briefly, then shuts down with yellow and green lights blinking. C822, R868 and R851 were burned. I need the values.

C822 = 470 pF/2KV ceramic disk; R868 and R851 = 2.2K ohm/0.5 Watt. You might want to check if P-channel MOSFET Q511 is leaky.

QUESTION NO. P413-4: Princeton EO17 monitor, R901, R902, R904 burned. I need the values and the possible reason for the problem.

R901 = 27K ohm, R902 = 12K ohm, and R904 = 12K ohm. These are in the ABL circuit, and they burn when the flyback has gone bad. Princeton or Korea Data Systems would have the flyback, fairly reasonably priced (800-237-9988, X234).

QUESTION NO. P413-1: Viewsonic monitor has a color problem. The color IC is VEY09P. Is there an equivalent for this IC? If not where can I get this IC?

No equivalents. VEY09P can be obtained from Viewsonic (800-888-8583), or from a Panasonic parts distributor, although stock is sometimes not available. Other sources include NationWide (888-634-7278), LJ Enterprises (800-627-8755), and CCS(800-356-1227).

QUESTION NO. P410-8: Mag DX17F monitor. I need the value of R360 and part number of ZD305 in the tilt circuit. Also, the range of the control voltage on connector W308 opposite the reference voltage of 12 volts.

R360 = 27 ohm resistor; ZD305 = 24 Volt zener.

QUESTION NO. P47-8: Dell 17fs-n monitor, video is very washed out with green screen and retrace lines. Focus works as does screen control. Voltages appear to be correct.

Check if there is a short between the green cathode, and either G1, or the heater. If there is no short in the CRT, then on the CRT board, check hybrid IC202 (Mitsubishi OEM# CP267P042A30), Q2B0, IC203 (LH2426H), and if necessary, the SMD IC on the back of the board, IC201 = AN93B04SCR (Mitsubishi OEM# CP263P05701). If you need parts, this chassis is similar to a Mitsubishi Diamond Pro 17, TFS6705SETK, so either try Mitsubishi itself (e.g., 800-447-7703), or else a Mitsubishi supplier, like National Parts Depot (800) 524-8338 or Comprex (800) 526-8611.

QUESTION NO. P411-7: ViewSonic V775 monitor (1882DC) no video signal displayed. I replaced the EEPROM ( re programmed ) and the monitor will work for a few days and it will damage the EEPROM and the same problem re-occurs. I am trying to get a replacement 40 pins controller for it (LSC44072IP) but I had no luck with Nation Wide and others. Where can I get the controller and is it really the controller IC at the soure of this problem?

Have you tried Viewsonic directly for your IC? Try (800) 888-8583, X6046.

QUESTION NO. P411-4: HP D2800A. The chassis of this monitor is similar to the Viewsonic 21PS IC (21HV4S). In regard to question P324-6 posted on your site is the missing color the green gun, and if so will replacing the VEY09P take care of the problem? This is an expensive IC ($60) so I want to be sure that is all that I need to replace.

VEY09P is the common fault for missing colors in the 21PS chassis. If you need to reassure yourself, here are a couple of things to try. First, if you get an on-screen display that is OK, the problem is more likely in the settings in the Eeprom, etc, and probably not VEY09P. Second, the usual fault with VEY09P results in an apparent lack of INPUT into the affected color channel, often misleading techs into assuming a defective output from the earlier IC (M52326SP). So swapping outputs for two colors from VEY09P will usually show that the green (or whatever) CRT gun is functioning. For the 21PS, at least, Green input should be pin #2, Green output should be pin #4, and Green Vcc should be pin #5 on the VEY09P (pins #1 = ground, #3 = N/C). By the way, save the old (bad) chip; since each channel is identical and independent, you can use this old IC, for testing the next suspect VEY09P, by temporarily replacing a suspect channel, with one of the two remaining good color sections (keep all wires short!). In fact, you might even try this here, and see if one of the other sections will drive the green channel properly. FYI, the remaining pins are #6 & #11 = Ground; #7 = Red Vcc, #8 = Red Out; #10 = Red In; #12 = Blue In; #14 = Blue Out; #15 = Blue Vcc; #9 & #13 = N/C. This should suffice, in case your chassis has a different ordering of the color channels for this chip.

QUESTION NO. P410-7: Mag DX700T monitor FCC IAWDX17T-II with shorted Q117. Parts list calls for K1113, unit has a K1284 installed. Cannot find a replacement or data sheets for a cross.

2SK1113 and 2SK1284 are fairly similar 2SK1113 is rated at 120 Volt, 3 Amp, 20 Watt, Rds[on] <0.4 ohm; while 2SK1284 is rated 100 Volt, 3 Amp, 20 Watt, Rds[on] <0.32 ohm. B & D Enterprises (800-458-6053; www.bdent.com) is listing 2SK1113, as well as 2SK1060, a device with Voltage and Rds[on] ratings more like 2SK1284.

QUESTION NO. P320-2: Several Dell D1528-LS monitors go blank shortly after powering on, the led remains green. Pushing the button off/on the picture appears for a moment then the same problem occurs. I changed the capacitor ( 220湩 400 V ) but it does not work.

I am not 100% sure if your screen is the same as mine but I have had similar faults on three Dell screens that go blank after about 1hour or longer. The fault was caused by the main Z80 based processor (test to see if control panels lights work correctly, if they have locked in one position or operate in a strange way this is likely to be the fault) which I think is available Richardsons.

I removed IC701 (Zilog 860204 Keyboard Controller) and reinstalled the same part after not finding a replacement. The monitor has worked now for 2 days without blinking. I suspect there is oxidation on the socket connections and removing and reinstalling the same part has made better connections to the socket.

QUESTION NO. P47-4: Mag DZ1595 monitor went down during a power surge and now blows the internal 10 amp fuse. I traced by foil runs to a shorted Q301 Mitsubshi FS7UM 165603 but I cannot cross it to anything.

Mitsubishi's FET FS7UM-16 is rated 800 Volt, 7 Amp FET, Rds[on]<1.85 ohm, 150 Watt, all in a TO-220 case. Most other FET's in this package will have inferior electrical specs, so either try to get the original, or else get FS7UM-18A, the 900 Volt member of this family. B&D Enterprises (800-458-6053; www.bdent.com) does list the 900 Volt FET. You might also try LJ Enterprises (800-627-8755; www.ljent.com).

QUESTION NO. P46-2: Princeton Graphics Ultra 17+ monitor came in with Q415 bad resulting in a full vertical display but only 1" of horizontal. Replaced the BU2525AF and the monitor came up with a perfect display and all controls work including brightness, contrast, focus, etc. In a hour the HOT blew again. Replaced it again and started checking waveforms. The only waveform that appears off according to the schematics is the signal on the H yoke. Says it should be 133 v p-p but I only show about 60 v p-p. All voltages check from 5v up to the 470v. 184v on the HOT. But, monitoring the temp of Q415 shows the temp climbs until too hot to touch. I have checked all caps and resistors in this area. Would also appreciate specs on the BU2525AF and D417, FMP63FG.

BU2525AF = 1500Vcbo; 12 Amp; 45W; Tfall < 0.35 usec; gain is 5-10 (7 typ.) at 6 Amp Ic; there is no internal damper. You may have mis-read the number for diode D417, but this sounds like a Sanken number, the closest to your number would be FMP-G3FS, which is a damper diode rated 1500 Volts, 5 Amps, Trr < 0.7 usec. But if this is the wrong one, you will need to repost the corrected number, or get the specs from either Sanken's website, or Allegro Microsystem's website (Sanken's North American rep). For this problem, try checking Q404, Q405, D406, D407, D417, L401, L402, L403, C440 = 3.3 uF, and R431 = 2.2 ohms. Also check the solder around this area, and the yoke connectors. Does this chassis have the upgraded "A" suffix versions, for IC402 = HIC402-PT1A and T401 = KDS2036A, installed? If not, consider installing the KDS upgrade kit with these (and other) parts.

QUESTION NO. P45-7: I need a cross reference on a two lead TO-220 type case (insulated) rectifier marked FMP G2F. It came out of the high voltage section (flyback) of a KDS 4250 monitor.

Sanken's FMP-G2FS rectifier is rated for 1500 Volts, 5 Amps, Trr < 1.2 usec. One source for FMP-G2FS is B&D Enterprises (800-458-6053; www.bdent.com).

QUESTION NO. P43-5: Princeton Ultra 70F monitor, the screen was very dim, I adjusted the flyback for a temporary fix but need a source for a cap. kit for it.

If the FCC number is IAWDX17FG, the OEM manufacturer is Mag Innovision, and you should either contact them, or get a cap kit from your supplier for the Mag DX1795 or DX17FG chassis. If it is this one, however, you may wish to check the following, regarding your dim display. First, try checking the -5 Volt regulator Q536 = 79L05 for proper output. If Q536 is OK, and the OSD itself is not dim, then this may be an Eeprom or a brightness/contrast settings issue. Go to the factory-mode setup display, and check if the contrast or brightness settings are set too low. If you need some details for doing this, see the answer for question P120-4, about the Mag DX17FG monitor.

QUESTION NO. P331-4: Several Apple applevision 850 monitors when switched on, hv comes up and raster is working. When the contrast button ius pressed once, the picture appears, but with strange adjustments. If you recall the default settings the monitor works just fine until you switch it off and on again.

Did you have these units hooked up to a Macintosh computer, with both video and ADB cables, running Mac OS 8 or later, and with the Applevision software, version 1.5.2, or a more recent version? If not, get the appropriate software, and set it up on a Mac computer with a known-good monitor. Now disconnect the good monitor, and attach the problem monitor, and start up the computer while holding in the Command (apple)-Option-A-V keys. Hold these four keys in, until the startup is completed (1-2 minutes). Enter display settings in the control panel, and see if they are retained. If still not working, the repair will at some point have to use the proprietary Apple software, Display Service Utility, found on the Service Source Companion CD-ROM, to download settings to the monitor, so it is likely you would need to take them to an Apple-authorized service center.

QUESTION NO. P330-6: Several Mag LX1564L monitors that power up OK, but have smearing where there is an icon or message bar. Brightness and colors are OK.

First, check/replace all the 1 uF caps on the CRT board. But, bad CRT's can also cause this smearing. Those chassis with Toshiba CRT's fitted are more prone to bad CRT's, than those with Hitachi CRT's. If the cutoff of the CRT checks bad, try restoring the CRT.

QUESTION NO. P31-5: Viewsonic E771 17" monitor that has a corrupted EEPROM. This part is used to store not only the user settings, but also the factory settings so replacing this part with a blank EEPROM doesn't help. I noticed there is a switch near the EEPROM that is labeled "normal" and "factory mode" but this has no effect. What is the procedure in using this switch to enter "factory mode"?

If there is an empty socket near the switch you will require the programing jig to dump the factory settings into the EEPROM. The socket should be a two pin (serial clock, serial data) but may have a voltage and ground pin. You could try approaching an authorized Viewsonic agent to borrow their jig, however it is unlikely that they will agree.

QUESTION NO. P330-5: I need the value of r241 found burnt out in an Acerview 76e monitor.

The value of that resistor is 10k ohm 1/2 watt.

R241 = 10K ohms. Better also replace C327 = 220 pF/2KV, and check Q301 = FET BSS89, R329 = 10K, and 3 Amp picofuse J013.

QUESTION NO. P329-6: We have a number of Samsung Syncmaster 15gle, cma5377l monitor with dim screens. crt emmision is ok.

Are you sure the tube is good? Samsung is very well known for bad tubes,especially samsung branded tubes. If tube ok check all b+ going to neck pcb. Check for bad caps in contrast circuit around ic101 pin 12(c105 and c107). Make sure you have good G1 and G2 voltages.

If those CRT's are made by Samsung, especially their tubes with the blue labels, I would still be suspicious of them. These can be bad, even when they apparently test OK for emission on some CRT testers, and are a very common failure item. If the filament voltage is at least 6 volts (6.3 optimal), and the G1 and G2 are not too low, I'd still suspect the tube. If you are servicing a number of the same units for a customer, a temporary swap of the CRT/yoke, with one from a functioning monitor, could tell the story. The bad tubes may brighten up if the G2 voltage is raised, or if the filament voltage is jacked up, but these would be temporary fixes at best. The only good solution for bad Samsung tubes is CRT replacement.

QUESTION NO. P328-5: Dell D2026T-HS Ultra Scan 20TX monitor. Initial problem is a very dim image. Investigation reveals that G2 voltage enters neckboard at approx. 1000 volts. By the time it reaches the CRT socket it is down to about 80 volts. I believe it should be at least 120 volts there. It appears that Q407 and Q403 are involved in controlling the G2 voltage. After temporarily installing a focus divider to bring G2 up to about 120 v. the image is much brighter , but there are now random retrace lines flashing across the screen. Everything else "appears" to be as expected.

The most common failure component for G2 problems on this chassis, is IC402 = CXA1907S, on the CRT board, Sony p/n#8-752-071-56 (get from Sony, or try CCS). The old IC is hard to remove safely; it works best to clip off each pin, and remove the pins one at a time. But before buying this IC ($40+), you might want to check first with a CRT tester, to ensure that the CRT has good emission.

QUESTION NO. P328-3: DX17Fe monitor. I need to identify three zeners diodes referenced ZD104, ZD105 and ZD501.

All these diodes are 12A2 - zener 12v.

QUESTION NO. P316-8: Acer 78ie monitor keeps blowing horizontal output transistor. Everything else appears to be okay.

Check for a mistuned horizontal flyback circuit. This results in higher than normal voltage on the HOT collector. Inspect the tuning capacitors (in parallel with HOT collector/H yoke) for bad soldered connection. Also check the tuning capacitors for leakage.

QUESTION NO. P327-4: IBM 2124 monitor with the HOT S/C. Replacing the device returns the monitor to service for a couple of minutes before getting very hot and blowing the transistor again. There is no evidence of HT issues when the monitor is on, as the picture is very good.

Whenever the HOT blows, check C335 = 220 pF/2KV disk cap off the HOT collector, and R214 = 15K, 1/8W, in line with C335. Replace C335 on even the slightest suspicion, it often seems OK when it is not. Also check C319, D316, D317, MOSFET Q317, coil L304 (probably damaged if burnt, or if it measures under 0.5 mH), and IC201 = TDA4858. Check the solder in the horizontal area, and around the diodes in the secondary of the power supply. Finally, ring the flyback.

QUESTION NO. P327-10: Apple M2943 monitor. On the CRT board are two sets of three resistors, white and orange. What do they do, how does one use them? I assume that one set adjusts the base values of the three colors and the other set adjusts the slopes. (I do have test patterns from Sonera Technologies which would be helpful for adjustments.)

You may be referring to the two sets of trim-pots, on either side of the CRT assembly. There are a couple versions of this Apple (different FCC numbers), so I cannot know if yours will be the same as the one I will describe. Facing towards the back of the CRT, on the left side are three closely-spaced trim-pots, towards the bottom. Top to bottom, these are VR304 (Red Bias), VR305 (Green Bias), and VR306 (Sub Brightness). On the right side, there are two trim-pots above, VR301 (Red Drive) and VR302 (Green Drive), and a third trim-pot, somewhat lower than those two, VR303 (Sub Contrast). Typically, the red and green biases are adjusted, to give a good grayscale; the drive controls are only adjusted if the bias control adjustments are not sufficient to give neutral grays, and it may then need a screen pot adjustment of the brightness, for the proper black level.

QUESTION NO. P327-9: Apple M2943 monitor, red is somewhat brownish, and orange (I assume it should be orange) is medium brown. Is there a procedure for checking and adjusting computer monitors?

Yes, of course there are procedures for checking computer monitors! In the case of your Apple M2943, there is a specific procedure Apple provides for its technicians, utilizing the Apple Service Source documents, and certain Apple-qualified hardware, like light-meters, etc. Their procedures are far too involved for this page. However, if interested, Apple has recently made it possible for any individual to become an Apple-certified technician (at least, in the US and Canada). Self-paced training provides instruction, and if actual certification is desired, an exam is taken. For more details, see Apple's website at support.info.apple.com/support/applecare_products/technician_training/features.shtml for the description of this program.

QUESTION NO. P324-6: Viewsonic 21PS IC monitor is missing one color. I need to replace the IC - VEY09. Checked the Viewsonic site, and I cannot narrow down to the actual page.

Try Viewsonic at www.viewsonic.com/desk/desk.htm , phone 800-888-8583, or email vstech@viewsonic.com. If there is an availability problem, you might also try Nationwide Electronics (888-634-7278; www.neiparts.net).

QUESTION NO. P323-9: Daytek DT1501BA1/MPR color monitor width always excessive even when internal width control turned all the way down, it acts but not enough. Also has rounded sides. Otherwise image is fine and all the other controls work fine. Replaced several caps but it did not solve the trouble

Try checking diodes D502 and D503 for reverse leakiness.

QUESTION NO. P323-7: Samsung SynvMaster 17GLi monitor has a loss of horizontal sync after about 5 minutes and gets progressively worse. The whole frame then shakes on a horizontal plane before total sync loss.

Are you getting an H sync signal to pin# 17 of IC401 when the unit goes off sync? Is there a stable 12V supply for the Vcc at pin# 18 (pin# 19 is ground), and are the caps/resistors off pins 10, 11, 12, & 13 within specs? If these are all OK, then try replacing IC401 itself, it is a known failure item.

QUESTION NO. P37-1: Mag DX1795 monitor, picture appears bright then after about 5 minutes fades to a black screen. Tried freeze spray no effect.

Is picture fading out or is there a sudden loss of picture? If fading out, check to see if filament is lit. If not, check heater circuit. Could be a bad connection at crt socket or on neck pcb. Also check heater B+ from power supply.

QUESTION NO. P317-10: Voxon mo-d1428 monitor has no picture and power led on front will not light up. I tested the fuse etc. I found one side of transistor was dead located near power supply. The number on transistor k1537. It can be substituted with an ecg-2377, where could I find this part?

If you mean where to get the FET transistor 2SK1537, it is listed by B & D Enterprises (800-458-6053; www.bdent.com) and MCM Electronics, (800-543-4330; www.mcmelectronics.com), among others. If you mean the ECG-2377, ECG replacements are obtained through their chain of distributors. Go to their website at www.ecgproducts.com , and find a distributor serving your region.

QUESTION NO. P316-6: I have 12 "bad" GVC M1448L color monitors (FCC ID DK4M1448) that all appear dead except for the bottom-most of three LEDS flashes a few times on power-on and then remains on very dimly. All these monitors died while working. There is no indication of HV. On the two that I have opened up, the screen filaments do not light up. The fuse is ok.

Try checking rectifiers D121 through D125, on the power supply secondaries. The "HER" rectifiers can go bad.

QUESTION NO. P316-2: Mag DX17F monitor, replaced the "usual parts" - only instead of replacing HOT w/exact replacement, used NTE cross. Unit worked for ~8 hours, then quit; then changed w/exact HOT(C4747) - noticed that NTE cross had "arced" to heatsink even though mica was used. Replaced flyback to no avail. In 640X480 unit will start to work then high voltage starts falling off. In high scan modes, high voltage starts to come up, but then goes away. Also, when in 640X480, screen is smaller than usual and gets smaller.

I would stick to the original HOT (C4747). Also check/replace Q116 (IRF740), Capacitors 123,120 (1uF/50V), 134 (1uF/450V), coil L105 (a good one measures 4.6mH and 175 rings on a Sencore LC102 using the coil setting).

QUESTION NO. P316-9: Daytek (Daewoo) DT-1731D monitor year March 1997 Chassis Orion. I need the part # for the flyback transformer as it has no sticker on it but some production numbers by Hosiden and Hyundai (Japan). I believe the location is T602. The generic part number or a manufacturer's part number would be sufficient.

The original flyback is FFA76017U, but these have become scarce, since so many have been dying. Recently, Daewoo has been substituting FFA76028U, which fits into the board after one extra pin is snipped off.

QUESTION NO. P316-1: Dell D1528 LS monitor, after one hour the display goes off. The high voltage remains and the monitor displays again if switched off and then on after a few minutes. The on time gets shorter with time. Capacitors C826 and C828 becomes very hot.

You should change the caps, especially C826, it gets leaky; also check C823 and C841. There is a good chance the Zilog Z860204PSC microcontroller (I701) is going thermally bad. Does freeze spray affect it? Does the front panel LED change color at shut-off? Try NEI (www.neiparts.net/cmparts/semiconrecent.html; 888-634-7278), or CCS, for a replacement Zilog if you need one. It has also been recommended to glue a metal strip to the top of of the new IC, and ground the metal, to protect it against damage from arcing. It is also possible the Eeprom (I703) is bad; if needed, try NEI or LJ Enterprises (800-627-8755; www.ljent.com) for the preprogrammed Eeprom.

QUESTION NO. P314-2: Apple Multiple Scan M2943 monitor. Red is absent in pure and combinations except white is a dirty white, obtained from green and blue (BTW, green looks more like yellow). R 562, 970 control Blue, R 532, 940 control Blue, R 502, 910 no effect. I checked the solders again but cannot find any defective ones. (I have already fixed three weak ones at IC MM1203 534.)

A common site for cracked solder is on the leads for the red driver transistor, located on the CRT board at the upper right from the back. But bad solder is widespread, so double-check or reflow the solder everywhere, including the black jumpers and the surface mount components. Also you may wish to check the red driver transistor itself, and check if the electrolytic capacitors are bad. If any caps are marginal, replace them all. This may be why your green is odd, as well as no red. Rarely, the MM1203 IC is bad.

QUESTION NO. P223-1: I need to identify transistor q317 in an Acer monitor fccid-jvp7134e4e.

Q317 is a mosfet. IRF 630. Good chance coil L 304 is also shot.

In addition to the previous answer, to prevent future problems with this monitor, replace c335. This is a 220pf cap at 2kv. Replace this with a 6kv version, these caps tend to cause a variety of problems.

QUESTION NO. P37-10: Gateway PMV1448 monitor does not sync at higher resolution rates. I can adjust VR701, VR102, VR103 and VR104 to get a stable picture at the higher sync rate, but when it goes back to the low rate it loses sync again.

First check if your video input rates are acceptable for this chassis. This unit was originally specified for 640x480 and 1024x768 NI resolutions, using horizontal scan rates in the 30-32 MHz range, or 47-49 MHz range. So, you maybe can get 800x600 resolution, also, but only at a 48.1 KHz horizontal scan rate (Sencore mode 30), not at 35.2 KHz (Sencore mode 8).

QUESTION NO. P310-7: Mitsubishi Diamondscan 17FS FFY7705SKTKL monitor Chassis X7705. When turned on, the degaussing coil activates, the brightness and contrast LED's start flashing, and one of the control select LED's just stays lit up. None of the controls have any effect and no picture is displayed.

The most likely fault is that you are trying to run this monitor with a standard VGA-type video cable. This model needs a video cable with Mitsubishi's nonstandard pinout on the monitor end. If you aren't using the customer's video cable, get it from them. If it IS the customer's cable, ask if they got a "replacement" cable recently. Otherwise, you may have to make up your own cable. The Mitsubishi cable's pinout has been posted before in this repair archive, if you need to look it up.

QUESTION NO. P39-3: Samsung Syncmaster 17GLi monitor has gone very dim. I suspect the lopt drivers q416 and q502 but as yet have not tested them. I am having trouble locating a sub for these, they are marked as C5129 5H.

If the CRT is also made by Samsung, it is rather likely that this is the cause of the dimness. Samsung CRT's often get poor emission after a couple years; the ones with blue labels are worst this way. You might check if the filaments are getting good voltage. If they are, check the CRT emission on a CRT tester, to confirm the problem. Bad Samsung CRT's do not restore, they must be replaced. The C5129 transistor's full number is 2SC5129. If you do need 2SC5129, then in the US, try B&D Enterprises (800-458-6053; www.bdent.com); in Europe, try Donberg Electronics in Ireland (www.donberg.ie).

QUESTION NO. P38-3: Digital (DEC) PCXBV-PF monitor. Replaced defective 93C56 EEPROM and now need to know how to program the replaced device. Do you use the front panel buttons or some sort of test-jig adapter?

If you check the FCC#, you will discover this chassis is actually made by Lite-On. Lite-On Eeprom's should be installed pre-programmed. The program for the Dell D1528-LS should also work for this one, if you have the program. Try LJ Enterprises (800-627-8755; www.ljent.com) for preprogrammed Eeproms, if you do not have it.

QUESTION NO. P224-3: Four Digital pcxbv-ez monitors, chassis - 46, fcc id bejcs592 with the same problem - dead, no power led, no high voltage. I rang fbt and checked hot, fuse good, 155 dc volts at switching regulator in smps. Seems like switching regulator in smps is not being turned on, no secondary smps voltages.

Trace back from the pulse width modulation IC VCC pin. Between here and B+ you will find a small (10uf-100uf) cap fed from one or more series resistors of fairly high value. These are often (totalling) 100K or more. Check the cap for low value or high ESR and the resistor(s) for open circuit. These components "trickle" down a startup voltage to the PWM chip and are common failure items.

QUESTION NO. P31-3: Sony CPD17F13 monitor powers up OK but picture smears to the right.

Check the gun transistors on the tube board. It is quite possible that one or more of these is running slow giving you a lack of high frequency response. Another possibility is a cabling problem from the computer. If you are running an extention cable from the computer VGA socket which is not shielded or is too long, you can get a lack of high frequency response also. Finally (last resort), your tube may be gassy - but I would make sure everything else has been checked first before you make this assumption.

QUESTION NO. P31-10: AcerView 76e monitor, the top half is dead. The bottom half is fine, except for a slight gradient in brightness from bottom up. Suspect that something is wrong with capacitor around IC 201, but need more info.

Check or replace the vertical IC (usually a TDA8351).

QUESTION NO. P31-2: Gateway 2000 Vivitron 1776 (Mag Innovision DX-17S) monitor out of focus. I adjusted focus control and the image improves but is still not clear.

Replace the video board on the CRT. You could do just the socket ( that is usually what it is ) but the bopard is most likely not that much more.

Sometimes the flyback on this chassis fails in the focus divider section, and puts out excess focus voltage. Check if the focus voltage is staying too high, possibly even arcing around the CRT board or socket. If the CRT fitted in this chassis is a Sony M41KNP16X, that CRT is known to get blurry with time, and may need to be rejuvenated.

QUESTION NO. P229-5: MAG DX17T monitor has horizontal sync signal traced by scope all the way to the neckboard. Monitor does not sync horizontally. There is a position on board for an 8-pin chip. Is this an empty position or is a chip missing?

The Eeprom, a 93LC66 chip, is location IC706; if this is the location that is missing an IC, get a preprogrammed replacement IC, from Mag. If IC706 is still installed, then for the sync problem, first try a microprocessor reset. Power up while holding in buttons 1, 3, 5, 7 (and NO others), inside the door, simultaneously. Do not release the buttons until the green LED has blinked four times; then wait a minute or so, for the reset to complete. If this does not permit the unit to sync up, IC706 might be corrupted, and need replacing with a new preprogrammed Eeprom.

QUESTION NO. P228-10: NEC 6FG 21" monitor, when turned on, I can hear the sound of H.V. charging the tube, but after 1-2 seconds, the H.V shuts down. Before this symptom, the monitor just worked at 640x480, not accepting more than this.

See if the deflection transistor Q581 and regulator Q5G6 are leaky or shorted. For the modes problem, you might ask if your customer has been trying to run this older monitor on a newer video card, with scan rates that are too fast (also stressing the deflection circuitry).

QUESTION NO. P21-4: Acer 7154E monitor FCC JVP7154E. The previous tech swapped original tube for Orion (M36KXU110XX61) with its own yoke coil not original yoke. This mismatch caused HOT to blow when driving above certain H freq. Where can I purchase a used original yoke? If this Orion tube is incorrect, what is a suitable tube sub supposing that yoke is taken care of?

It is MUCH easier to substitute an entire CRT/yoke assembly, than to try and fit another yoke onto a CRT, and then afterwards get acceptable convergence. If the horizontal and vertical yokes of the original and replacement yokes have about the same inductance readings, and the CRT parameters (neck size, diagonal, pinout, etc) match, a CRT/yoke combination usually can be substituted. For 15" CRT's of this type, I would guess that the vertical yoke is about 6 mH, and the horizontal yoke is about 0.18-0.20 mH inductance. If your replacement CRT has a yoke with about these values, it seems more likely to me that there is an additional fault that is blowing the circuitry, than it would be the fault of the replacement CRT/yoke. If the horizontal yoke inductance is closer to 0.3 mH, then it is too slow; find a closer replacement.

QUESTION NO. P225-7: I am trying to identify components for the Digital GDM1961 21" monitor, i.e. STK7468 IC, C90M & C91-02 diodes and FT9620 MOSFET. I have traced the IRF9620 from International rectifier and SFP9620 from Fairchild as possible alternatives for the MOSFET.

STK7468 is a discontinued Sanyo device. The diodes sound like Fuji Electric ultrafast rectifiers. C91-02 would be ERC91-02 (3 Amp, 200 Volt, Trr < 35 nanosec), and C90M would be either ERC90M-02 or ERC90M-03 (200 or 300 Volt, 5 Amp, Trr < 35 nanosec), depending on the missing suffix.

QUESTION NO. P222-3: Proview PV-850D monitor is dim. Hot went bad, replaced HOT. Had arcing on collector to yoke (red) trace, hair line crack fixed with heavy solder trace. Still have dim problem but sharp image. Voltages and signal seems OK. Could it be the TLS1233 or sub-bright circuit? This picture tube is manufactured by ERS not a Samsung. Is it the tube?

Bad (dim) CRT's are very common on this chassis. There is some chance the 6.3V supply for the filaments is low. Scrape off any of that brown glue that goes conductive. This manufacturer uses that all over, on the P/S board, CRT board (G2 area?); also check the adjustment pots (sub-bright pot?), as this glue can sometimes seep into a pot and ruin it. The TLS1233 is a Texas Instruments RGB amp IC; if you want to troubleshoot it, get the datasheet at www-s.ti.com/sc/psheets/slvs126c/slvs126c.pdf as a PDF file.

QUESTION NO. P217-4: Philips C2082 (DAS / A, May 1993) monitor, after some seconds of selftest, it displays the text "Gen. failure" in its display. I need the values of R849 and R869 burned beyond recognizition and why they are blown.

The resistors have the same value, 68 ohms 1/4 watts for both.

QUESTION NO. P216-3: dx17f monitor has r137across q116 burnt. I need the value. I replaced fly back and q109. I took a guess on R137 and plugged in 10 ohm 1 watt. Switched on the monitor and it blew again.

Unfortunately I cannot help you with the value of that resistor but here is a list of components to check when you have this problem: Q109 (C4747) HOT, Q116 (IRF740) FET, Caps C123 and C120 (1/50v), C134 (1/450), L105 (large coil, I measured 4.6mH and 175 rings on a good coil using a Sencore LC102). Also you may want to check C134, D116, R177 (1ohm/1W).

R137 is a 120K 1\8 W resistor.

QUESTION NO. P218-5: HP D2804A svga monitor with a very dim picture, the image is still very crisp but way to dim. Brightness and contrast controls work but seem as if the range of the brightness is affected by something like a bad cap or transistor in the brightness control section. The flyback and crt seem fine.

This unit is known for having bad (dim) Samsung CRT's, so see if its CRT is a Samsung. These CRT's tend to go bad by losing emission; try checking the CRT's emission levels with a CRT tester. But it is also possible there is a bad electrolytic filter cap on the 6.3V supply line for the CRT filaments, so also check that supply line for low or ripply voltage. If the heater voltage & CRT are both OK, then check the electrolytics on the output side of the power supply.

QUESTION NO. P218-6: Samtron SC-428US(E) monitor with no vertical deflection. R201 is burned beyond recongnition (I need the value) and IC-201,a TDA8351, has a hole blown through the middle. This looks like a B+ current limiting resistor to IC-201.

For Samtron SC-428PS TDA8351 is IC301 (instead IC201, seems to be similar) and the value of R301 (R201 from 35V) is 100 ohms 1/2W (pin 6 TDA8351).

QUESTION NO. P218-3: IBM G70 monitor, when powerd up the led blinks green/orange. The high voltage comes up but there is no picture. With or without video signal the problem is the same. Already replaced processor and keyboard assembly for no good. What does the blinking led means (I believe the processor senses a fault condition somewhere)?

Sounds like a video card problem. Try swapping known to be good card with old card and also try switching slots.

QUESTION NO. P216-6: Samsung 17GLSi 7379L monitor has no horz sweep. Vertical is ok, high voltage ok. Replaced ic 401-horz o/p transistor-Q405. Did not help.

Try checking Q407 MJF16212 and Q401 IRF610. This is a common problem with this unit.

QUESTION NO. P214-5: Sony Trinitron 200ES monitor powers on, seconds later clicks, power led flashes, crackling. No hv, fuses ok.

Check C582 = 1000pF/2KV, also D504, D505, D903, D944, Q503, and IC904 = TDA9105. And check for bad solder joints, or bad crimp connections on any jumper wires.

QUESTION NO. P214-2: CTX 1451ES Monitor has no power and no lights come on. Previously, the picture became fuzzy, jagged and scrambled in Windows 95, seemed ok in DOS. Tested Fuse = ok, Power cables = ok. Found bad diode (D104) partial markings of diode BYV E PK. Circuit board is charred under the diode. Traces test good to the next component on each end of the diode. What are the complete markings of D104 and what other components should be checked if replacement of D104 does not solve the previous problem?

The 'PK' is actually 'PH', for Philips, D104 = BYV36E (a NTE571 should sub). C722 is a common failure, and probably should be replaced. Other parts to check that may be damaged may include Q406, Q407, Q410, Q701 (HOT), R415, R434.

QUESTION NO. P210-6: AOC CM-335 monitor with poor horizontal deflection, around 4 cm short, on both sides. I adjusted carbon core coil near horizontal circuit but image still not wide enough. Are there other adjusting points to check?

First, AOC CM335's are not full-screen monitors. Expect about 1 inch of black border on each side, that is normal. To widen these, adjust L402, or raise the B+.

QUESTION NO. P210-5: I found in the forum that Glen Wilson found a way to connect the 15 pin pc to a 15 pin 2 row mac monitor. I have a mac monitor with 10 pins and 3 larger plugs which appear to be for the red green and blue inputs. How do the rest of the wires convert or what does each pin on this type of plug do?

Some Mac and Sun monitors use a "13W3" video connector to the monitor. See website www.ccmr.cornell.edu/~putnam/pinouts.html for the 13W3 video pinout description.

QUESTION NO. P24-8: Compaq QVISION 200 , model 480 20 pouce. J'ai localis� la panne du moniteur ( apparemment c'est un classique) la pi鋃e qui permet de regler le G2 et les 2 focus. Malheureusement , je n'arrive pas � trouver une entreprise suceptible de vendre cette pi鋃e. Quelqu'un pourrait-il me donner une adresse pour commander ce composant sp嶰ial Voir un sch幦a 廦uivalent que je pourrais monter sur le bestiaux ?

To obtain the Fimi-Philips G2-Focus Module for the Compaq 480, Qvision 200 monitor, for North America, inquire at LJ Enterprises (800-627-8755; www.ljent.com); or if you are in Europe, inquire from Tony Bailey at I.C.H.E. (www.iche.com ; email, tony@iche.com ), in the United Kingdom.

QUESTION NO. P24-2: Princeton 17" multiscan monitor "ultra 17". Received into shop dead, had blown fuse. Replaced shorted HOT mjw16212. Also q801 2sk2141, zd801 12v zener part# z12c, and c818 in power supply. Now powers up to 25kv with signal applied and then shuts down. Have checked many caps and other common components that usually fail. It also has seperate rgb/bnc's in rear chassis.

Check Q415, Q416 (and its 1 ohm drain resistor), C451, D419, D420, T401, T802, ZD401. Also, check the flyback (can get from KDS, the manufacturer), it has an internal cap at pin# 13 that sometimes shorts to the HV anode. If these are OK, see if VR901 is setting the HV too high; you should have about 26KV on an HV probe, or if shutdown is too quick, try lifting the base lead of the HOT and measuring the voltage off the HOT collector (about 180-185 Volts) instead. Also, has this chassis had KDS's recommended upgrade done? To check, see if the part numbers on the hybrid IC IC402 and transformer T401 have an "A" suffix. If not, you really should install the KDS upgrade kit with these updated "A" parts, to help avoid comebacks.

QUESTION NO. P22-9: Mitsubishi HC3925 IDBGBhc3925K 20 inch Diamond Scan, 1991 vintage that has seen very little usage. Customer indicates this is so because display has always been washed out. Sub bright adjustment improved picture to about 80 percent. I cracked the seal on the screen control and with a slight 32nd inch twist, I had a perfect display. After running a few minutes, the screen was black. H.V. is still present. Filaments still glow. Proper video is being recieved. A quick toggle off and on will see a momentary raster flash containing an image of my computer desktop. I returned the screen control to its original position to no avail. I shut the monitor down hoping it was protection circuits but all I can think of at this point is that the increased voltage from the screen adjustment futher weakened an already bad connection. Is this likely and if so where do I start looking?

Replace the flyback transformer.

QUESTION NO. P21-9: NEC JC-1402HMA monitor. R632 was blown beyond recognition, I need the value of this. R623, R624 were blown also.

NEC's tech website lists R632 as 1.2 K ohm, 1/4 Watt, 5%, carbon, part# 40175175.

QUESTION NO. P21-5: Gateway Nr CS1776LE monitor. Cannot locate a replacement for D103. It has the letters IDQ and U64E written on the body of the diode.

Those markings actually should read "1DQ 06". D103 is an 11DQ06, a Schottky rectifier, rated 60 volts, 1.1 Amp, made by IRF. If you need a supplier, Digikey (800-344-4539; www.digikey.com) carries these IRF Schottky's.

QUESTION NO. P127-8: Dell D1726S-HS Monitor powers up and comes on, good video but relay will start clicking. This is intermittent, and the screen will blank. It does not cycle at any given interval. Sometimes unit has played several minutes, 30-45 before doing and others does it when first fired up.

This could just be a bad solder connection somewhere. Also, in one case of this symptom, on a related chassis, it was caused by a 7805-type voltage regulator (IC651), which was being overloaded a bit, and occasionally activated its internal shutdown circuit. Replacing it with a heftier regulator (a L78S05CV from Mouser Electronics, 800-346-6873) with better heatsinking solved that one. Perhaps a corresponding voltage regulator IC on your chassis is doing this. If either of these is not the cause, then I'd check out the hybrid IC, HIC601 = MP17H.

QUESTION NO. P126-1: IBM 9527 monitor displays only a vertical line.

Failure of the horizontal deflection circuitry, or open horizontal yoke. Check transistors T32 and T48, and their associated components (B+ line resistors, B+ regulator FETs, inductor M3, etc). Check generally for bad solder connections.

QUESTION NO. P124-8: Applevision 1710 M2935 monitor when plugged in led light does not come on and no power. As power cord touches power supply a single loud ticking noise is heard but then no power.

See if AC is reaching the bridge rectifier. This model uses a solid-state switch to apply the AC to the bridge, which is controlled by the microprocessor on the CRT board, via Triac optoisolator MOC2A60. If the optoisolator is not turned on, the unit will seem dead. This shutdown can be either real, due to bad components, or false, caused by a defect in the fault-sensing circuitry. If there aren't any bad components, but the microprocessor is still unhappy, and not turning on the unit, the processor board may need replacing, or its settings may need to be reloaded, using a jumper & the Display Service Utility found on Apple's Service Source Companion CD.

QUESTION NO. P127-3: What type of transistor is Q301 in an Acer 7276e monitor? The monitor is not passing the Horiz drive signal past this transistor. I read 100 Ohms from base to emitter in both directions. Markings on the transistor are only J9 S S 89.

Q301 is BSS89, a small N-channel DMOS FET, made by Philips or Siemens, rated at 200 Volts, 0.3 Amp, 1 Watt, Rds[on] < 6 ohms. The pinout is S D G, despite Acer's misleading silkscreens, and it has an internal source-drain body diode. If this FET has died, you should also check the HOT = 2SC5048, C327 = 220 pF/2KV ceramic disk cap, J013 = 3 Amp picofuse, and resistors R241, R326, R328, R329.

QUESTION NO. P120-4: Mag DX17FG monitor has no video when it is connected to a known good computer. I do get video "No Signal Present" when the monitor is disconnected for the computer. When the monitor is once again connected the "No Signal Present" video disappears, so it does know that a signal is present. I replaced the 3-channel video amplifier chip part # M54734SP.

Since you get some video, most likely it's a settings problem. Enter setup mode, by powering on unit while holding in both the Up(+) & Down(-) front panel adjustment buttons. Press menu button, enter OSD color bias menu, and raise the brightness and contrast limit values, using the Up & Down buttons, & Enter button. If individual colors need adjusting, set the individual color bias video gains with the Up, Down, & Enter buttons. At the end, power off unit for a few seconds, and then check if changes are saved. If this does not work, the Eeprom (IC703) may itself need changing. Less likely here, since you do see the video message, but a common problem for dark screen, is a bad Q536 = 79L05, a small -5V regulator IC, at the chassis front under the CRT.

QUESTION NO. P118-8: HP a4033 (Sony GDM20E01) monior with the same Fcc number (and problem) then question P97-6. I checked all parts but nothing. One thing that I found is 200v at anode of flyback instead 40kv, so I think is the flyback but where can I find it? Sony cie is writed on the top of the flyback and the only number that I found on the flyback is 8-598-929-00.

You get the flyback from a Sony parts distributor, using the Sony part number. For the 20E01 chassis, this is part# 1-453-162-11, which also replaces an older flyback, part# 1-453-151-11. These flybacks, however, are about $140 US.

QUESTION NO. P113-9: Voxon fccid LFVDX-1764N monitor. Power indicator light comes on, hear a single click,but no picture. FCC id says its Korean Dae Sun .

Check the HOT Q510 and C528; the flyback and its screen pot should also be checked.

QUESTION NO. P113-6: GVC/FCC ID#DK4M1448 monitor. The power LED flashes constantly. No blown fuses or cracked boards.

Check the diodes on the power supply secondary for shorts (D121, etc.).

QUESTION NO. P111-6: Two Smile GBVCA6736SS monitors come on in power saving mode with the signal cable disconnected but with a signal applied, the relay clicks on and off. The hot is shorted. Is the 2SC5229 in these monitors flakey or does something else need to be replaced also? Can I replace this with a 2SC5230 as it looks like a better part?

Try checking D104, D105, Q103, Q105, & R111. 2SC5229 & 2SC5230 are two very small, low-noise UHF transistors, made by Sanyo. They have the same electrical specs, just different packages. If that description doesn't fit what you have, then your transistor numbers were in error.

QUESTION NO. P111-5: CTX 1451es monitor has R652 charred beyond recognition (what would the value be)? This monitor was subjected to drywall dust (which may have caused the problem). I suspect that I need to shotgun Q623 & q624. Anything else ? As I recall the green gun is non functional.

In this case, the circuits for driving the color guns are most likely identical (and they were). I was able to determine my missing component from one of the other circuits.

QUESTION NO. P16-3: NEC JC1743UMA monitor (XP17) turns on but no HV or picture.

Check Q541 (HOT) and Q572 (P-FET).

QUESTION NO. P1227-10: Gateway Vivitron 15 CPD-15F23 monitor manufactured by Sony. After powering on, screen is green with ghost-like images and then it gets really bright until it shuts down.

If the video amp IC is LM1207N, try checking it for shorted outputs.

QUESTION NO. P16-8: Link LN15E monitor FCC LXMWY-1575PES. The hot had blown which I replaced, I put it on soak and it was fine, but when I adjusted the width the whole picture expanded vertically and horizontally and eventually it blew the hot again.

Did you check/replace C226 = 10uF/100V, in the base driver circuit?

QUESTION NO. P15-1: HP Ultra VGA 1280 Model D2807A FCC=ACJ93312116 (Actually a Panasonic monitor.) I need a source for video drive circuit (IC) labled "EYO7P".

"EY07P" is a Panasonic IC, so a Panasonic distributor can get it. One can also get it from Viewsonic (800-888-8583, vstech@viewsonic.com), since this IC gets used in some Viewsonic monitors made by Matsushita. For example, VEY07P is IC1302 (Part# E-IC-0401-0032) in the Viewsonic 1782-2 monitor. LJ Enterprises or CCS are also possibilities.

QUESTION NO. P1223-5: Daewoo CMC-1501BA1/MPR monitor, the picture is too far to the right, cannot adjust it back to normal. I replaced the vertical IC (TDA 1675A).

Change the large diode (unknown value) as it supplies power for the hor circuit and can be blown but not test in board as defective. Also there is a adjustment that can be made onboard to correct this check circuit in that area.

QUESTION NO. P1217-2: Shinho SM 585F-NB monitor has a pincushion problem. Replaced ic204 (tda4858) no luck. I suspect a L204 coil.

Try replacing capacitor C225 = 4.7uF/50V.

QUESTION NO. P127-2: Philips 107B 17" SVGA (PB7402) monitor. Almost completely dead. Power LED goes on momentarily then fades. Little (if any) initial voltages then all go to zero. No clicking or humming whatsoever.

Look for any smaller electrolytic caps in the SMPS that are rated at 100V or higher and replace them. I found that if they are even on the outer edge of their rated tolerance, the power supply won't start-up.

QUESTION NO. P1217-9: Relisys re767 monitor shows a double line of dots that look like pixels that run vertically down the screen intermittent. Color and position vary.

This turned out to be a software problem. Not enough ram running win98.

QUESTION NO. P1216-4: (5) five Proview 772IM monitors FCC IJEPV-772IM with shorted H.O.T. I replaced the transistor (Q615) with the same type 2SC5251, each time. The transistor blows again after 24 to 48 hours of burn-in. I rung the flybacks and yokes, checked for problems in the B+ circuit and checked the ESR on all electrolytic caps.

Try 2SC5207A instead of 2SC5251; this type can work in PV772IM chassis where the 2SC5251 fails after a couple days. If you need a source, try B&D Enterprises (800-458-6053; www.bdent.com).

QUESTION NO. P1217-3: Samsung CFG9637L monitor (fcc id# A3LCFG963). Replaced shorted Q504, the HOT for FBT (not yoke). Power up but no HV and no B+ at Q504. Most voltages seem ok and others a little high. I cannot find where Q504 gets its B+ from.

Check if R508 = 3.3 ohm is open; replace C505 = 47 uF/35V, it gets bad ESR and can cause Q504 to fail, as well as excess power dissipation.

QUESTION NO. P1213-9: Sony GDM-2038/UC monitor. I replaced the HOT. The High voltage comes up for about a second then shuts down. While the monitor is on, the power supply squeals, but all the voltages printed on the board are present. I am pretty sure the power supply is O.K. I am getting about 145v for the B+. Is this right?

Was the HOT shorted? If not, your problem sounds very similar to the problem I had with a GDM1937 (digital controls). This unit switched itself off by cutting the power from the HOT. All this was caused by a defective DAC (DAC8408) on the microcontroller board (board N) which controls the vertical deflection. Supposing these monitors (Sony is re-using designs quite often) have the same circuitry you can check pins 2,3,4,6,7,8,21,22,23,25,26 and 27 on the DAC. None of these should have 5V on them.

QUESTION NO. P1210-2: Trying to locate a flyback for a DEC VT220 monitor. Only marking is 16-26299-0.

That is a correct part number. In Canada call Data Display 1-800-561-9903. In the USA, Call Computer Component Source. Sorry, I do not have a phone number.

QUESTION NO. P129-8: CTX 1451C monitor. I need the value of the FET Transistor in the power supply. Has S, G, D labels (FET).

The number of the fet is a 2SK955.

QUESTION NO. P126-2: Tandy 25-4044 monitor made by Samsung. No vertical sweep, slightly reduced width. Have made visual check for burned components and solder joints.

If no vertical sweep, check yoke continuity, vertical IC and if vertical signal is rechting vertical IC. If there is just reduced width, then check for failing electrolytic caps in the vertical section and the width control pot.

QUESTION NO. P1118-5: Pixie PBC-1450 monitor takes 5 - 10 minutes for the picture to come on. When it does, the picture is real dark. After 10 - 15 minutes the picture quality and brightness are excellent. Screen is also darker in DOS than it is in windows.

Check the filament voltage - if it rises along with picture brightness then check for bad electrolytic caps in the filament supply.

QUESTION NO. P1129-9: What is the procedure for removing the SUPERVISOR password on an IBM TP600 Series? The customer does not want to pay for a new mainboard. Please note that this is the supervisor password bypass that is required, not the user password.

Connect the CMOS jumper to remove the data from the eprom then enter the setup mode, at bootup, and reconfigure the system. Or find the backup battery and remove it from the m/b for about 1 hour, allowing the system to totally discharge. Reinstall the battery and proceed with the setup. Not for the weak in heart.

QUESTION NO. P127-10: Apple M2943 monitor (FCC # BJMCM15VB UL # E132236 5K36) This unit has power and data on screen. Has brightness control but has no contrast. Have resoldered CRT board and replaced m1203 on CRT bd.

Are you seeing the voltage vary (from under 2V to over 6V) at pin# 12 of the M1203 IC, as the contrast control is adjusted? Is the contrast capacitor at pins# 2 & 3 OK? Is the IC getting a good pulse signal coming into pin# 14?

QUESTION NO. P122-9: NEC Multisync 4FG, JC-1531VMA monitor dead, power light does not light. Disconnect leads from power supply to main board, check power supply out on 24, 80, 150 all fine. Connect all leads except 150 back to power supply, everything works including power led. Seems to be shorted out on 150 side.

Very common with this model. Check Q505, Q510 (replace IRF9610 with IRF9620), D506, D507, ZD502 and C520. Also check for bad electrolytic caps in the horizontal/HV section.

QUESTION NO. P128-8: AOC cm-735 monitor. I tried to demagnetize the crt but there are stains which cannot be demagnetized and they are at the same place (cannot be moved). Is there some way to remove this coloful stains on the crt

Either the tube was dropped and the shadow mask is damaged or the purity magnets are damaged/mis-aligned.

QUESTION NO. P128-7: Compaq 472P monitor, high voltage is present, no brightness, black screen.

Try turning up the internal brightness (G2) control. If you can get a dim/dull image then check filiament and cathode voltages, if good then tube is probably bad.

This is a Samsung chassis, and the most likely problem on these, when there is high voltage still present, is a bad CRT (no repair). But check that there is 6.3 volts on the filament supply to the CRT, and that the G1 and G2 voltages are not too low, just in case.

QUESTION NO. P128-10: Gateway 2000, EV500 monitor, after about 10 minutes or so the brightness will fade in and out. If I smack the monitor it will come back to full brightness. Now all I get is the power led and a couple of relays clicking. The guns do not glow at all. I resoldered all high voltage components thinking I had an intermittent connection.

Check the big transistors in the horizontal section, 2SD401 and 2SC2316 short out. Also check ZD902 and for bad electrolytic caps.

QUESTION NO. P126-1: AcerView 7176ie 17" SVGA, made July 1996. During warmup there is excessive highlight tearing, sometimes covers whole screen in bright green tint. Sometimes accompanied with high pitched whine (VGA freq. range). After a few minutes warm-up problem disappears. Only happens after the monitor has cooled down for an hour. Replaced all the caps on the color board, no help. Filament voltage stays constant.

Replace capacitors 3950,3951,3952. They are near the heatsink around the FBT. I forget the value but they are 450V.

QUESTION NO. P128-6: CTX 1565 monitor with a very bright picture with lines. After five seconds the picture jumps to one point and the monitor switches off.

You probably have an open resistor or solder connection in the G1 circuit. This allows the CRT guns to go "full blast" by the time it's warmed up and cause the shutdown. The resitors in the G1 circuit are usually at least 220K and often 1 Meg or more. Sometimes you will find two resistors in series. Check the solder on the CRT neck board as I have found it to be poor on this model CTX monitor.

QUESTION NO. P123-1: IBM P70 6554-603 monitor, Sony chassis - FCC id AK8GDM17ER01, fails to start. When turned ON, the power indicator LED is green then turns orange (or cycling green/orange if the monitor is connected to the CPU) after about 5 seconds. During the 5-sec LED "green" time, dc supply voltages of 180v, 75v, +/-15v and 22v are present at connector CN640. Also during this time 12.7v supply is present at SMPS IC601. All aforementioned voltages disappear after the monitor shuts down ("orange" LED time). CRT filament is momentarily lit, and the usual high voltage crackle and half-second bright flash at the back of the CRT is observed during this 5-second start-up time. These other supply voltages were also observed 6v at connector CN671, and +/-15v, 5v at CN670.

Try to change the tda (ic) controls the horizontal and vertical and the B+ and you have the protection circuit controlled by this one. Good chance.

QUESTION NO. P115-7: Compupartner #CMVN-1428 monitor has shadow (on icon, it's easy) and i try first by change the IC video driver but nothing.

Shadows (not ghosts) are caused by bad electrolytic coupling capacitors in the color section. Also check for proper filament voltage. A bad/worn out crt may also be the problem.

QUESTION NO. P114-9: TVM MD-14III low-radiation color monitor. The images on the screen are shrunk (vert. and horiz.) and the images are very dark.

Check if B+ and/or HV is at correct level. Most likely dying electrolytics in the power supply as both horizontal/vertical/brightness are affected.

QUESTION NO. P121-1: Compaq 480p (QVision 200, 21 inch) monitor which has focusing problems. The picture is blurred around the middle of the screen. When the brightness is turned down the blurring seems to go away, also this blurring only seems to happen at higher resoultions (1024x768 and upwards). At lower resolutions the picture is fine.

These chassis are made by Philips/FIMI, and a common problem is the focus/screen block. FIMI installs three versions (not interchangeable), depending on the CRT fitted, so get the number off yours, it is printed on the side of the block facing the CRT. In the US, possible sources can be LJ Enterprises (800-627-8755) or Nationwide (800-659-3186, X225).

QUESTION NO. P1124-8: IBM 2124/Acer 7154E monitor came in with shorted HOT. Replaced that & c335 220p/2kv, r214/15k. still no HV start. 48v on collector of HOT, Q316 * 317 OK. deflection IC TDA4858 warm to touch.

The most probable culprit is a shorted coil L304, p/n#19.40133.001. It's best to ring it, but if you cannot, and it's testing below its 2 mH inductance, or it appears at all discolored or burnt, or it runs very warm, replace it. Also check D316 and D317. Note, sometimes, the diodes & transistors in this unit will not test out as shorted, and yet still have high reverse leakage, so be aware of this.

QUESTION NO. P1122-10: (2) Viewsonic 17G monitors with the same problem, when you adjust the on-screen settings, it works fine. However, when you shut the monitor off, the settings are lost. Is there an eeprom that holds these settings?

First, after you changed all the settings, did you save them first, by pushing the button on the right before exiting? If yes, but still no save, then in the 17G, there is an Eeprom IC902 = X24C08 type, but I do not know if this IC is the same in all "17G" Viewsonic models (17G, 17GA, 17GA-1, 17GA-2, 17GS, 17GS-2, etc). For specifics on which Eeprom, and version, is in your model(s), and whether it needs to come preprogrammed, try emailing Viewsonic with specifics, including chassis#, etc, at vstech@viewsonic.com.

QUESTION NO. P1119-6: Samsung sync CQB4147 monitor FCCcsysc-428pt takeS 5 - 10 minutes for the picture to come on. When it does, the picture is real dark. After 10 - 15 minutes the picture quality and brightness are excellent.

Sounds like a bad electrolytic filter cap. If the problem is that the CRT filaments are taking this long to glow brightly, or have a low supply voltage, check electrolytic caps off the filament supply. If those are OK, check the main filter cap in the power supply for bad ESR or leakiness. If C604 is bad, R603 = 3.3 ohm may have suffered damage.

Another common problem with these units are the tube itself. This tube will barely outlast the warranty period of the unit.

QUESTION NO. P1118-9: I need the cross for a ZTX 948 transistor for an IBM G50 monitor.

Believe it or not, that little ZTX948 PNP transistor is rated for over 5 Amps! Do not use a cross, get the original. If you do not have a local supplier for Zetex Super E-line transistors, try B&D Enterprises (800-458-6053, www.bdent.com) or Digi-key (800-344-4539, www.digikey.com), who both list ZTX948 in their stocks.

QUESTION NO. P1117-2: Gateway 2000 CS1024NI2 monitor has R334 burned beyond recognition. Can anyone ID this part? It is right next to Q303, a D799.

For Gateway CS1024NI2 (FCC#IAWLX1450), R334 = 1K ohm / 1 Watt. It would be prudent to also check the components mentioned in the answer for Monitors question # P119-9.

QUESTION NO. P1115-10: CM-8428 MX monitor FCC ID# EVOKD-1450. What is the value of R915, burnt beyond recognition?

For a monitor with that FCC number, R915 = 22 ohm. Probably should also check R905 = 68K; C953 = 470uF; ZD913 = 100V; ZD914 = 30V; U902 = TL431; the 3842 IC & ZD902; and probably also the HOT (Q610) and its B+ line resistor.

QUESTION NO. P1115-7: HP a4033a monitor. D824 was shorted and PS501 was open. R868 is burnt & open, what is its' value?

In these Sony chassis, R868 & R851 are the same value, 2.2K ohm, 0.5 Watt. But there is a variation out there, different from what is seen in some of the other Sony's or even in these Sony's schematic, and in those the value of R868 = 1K, and R851 = 5.6K.

QUESTION NO. P1115-2: Dell ultra scan 17FS-EN monitor with no green color. I need the value of "IC201".

This is a similar chassis to the Mitsubishi TFS6705SETK; IC201 = AN93B04SCR, p/n# CP263P05701, a 28-pin SMD IC on the video board. Maybe try Nationwide.

QUESTION NO. P1110-6: Mag dx17f monitor. I replaced the usual list of parts for a dead unit and it powers ok,but I can not get full width in the screen. It goes to about with in a half inch on each side. Vertical is fine.

In cases where the width adjustment has insufficient range, check if the B+ at the collector of the HOT is low, like 60-65 VDC in VGA mode. If so, try to widen it out by tweaking the HV adjust potentiometer VR105 to bring the B+ up a bit, you can usually go as far as 75-80 VDC of B+ on the HOT collector. I think some replacement parts can be a little inefficient, like certain versions of L105 that run warm, so this is probably just bringing the B+ back to where it should be. If the HV trip (VR106) happens to be set too sensitive, re-adjust VR106 to trip when VR105 is set to give 29.5 KV on your HV probe, and then turn VR105 back down to the acceptable B+ running level.

QUESTION NO. P119-9: Gateway 2000 Crystal Scan CS1024NI2 Monitor. I need the the value of R241 and the specs for ZD202.

R241 = 20 ohm; ZD202 = 20 Volt, 1 Watt. You should also look for damaged electrolytic capacitors around the middle of the board, like C315, C316, C335, etc., and suspect possible damage to the TDA1170 vertical chip. And before you power it up, check out R325 and R335, both 33K ohm/2 Watt, in the power supply, and be sure these have good values and their solder is OK. Or just replace them. By far the most common problem, when ZD202 and R241 burn, is that one of those two resistors has gone open or up in value, and the resulting overvoltage is what destroys everything else.

QUESTION NO. P118-2: Mag MXP17F monitor with no horiz. sync. Signals are getting to sync processing chips, most of which have been changed including the LA7855, TTL chips. The front controls operate normally, including remembering factory and user settings, but I suspect processor IC and eeprom.

The horizontal freerun frequency is factory programmed. The only way to restore this data, if lost, is to return the unit to MAG for re-programming. The voltage on pin#14 of IC109 should be approx. 4.62VDC on 640 x 480 mode (h.freq of 31.5kHZ). If this voltage is high & does not change with the horizontal frequency inputted, the data is gone. Don't waste a lot of time on this one.

This is a common problem with the MXP17F chassis, and unfortunately, it is a problem that cannot be repaired in the field. The Horizontal frequency reference voltage data on this particular Mag model is factory-loaded at time of manufacture, using Mag's proprietary interface. If the data is lost, the only way to reload it, would be to send the unit to MAG.

QUESTION NO. P118-9: Mag dx700t monitor. Q106 shorted and R173 open. Replaced and now runs very hot. How hot should it run? Have contacted Mag but they were no help.

With R173 and Q106 bad, also check R212, C117 = 0.0062 uF/1600V, C548, D101, D109, and L105 = Mag p/n# LM*-751-401*0 LSE. I'd suspect L105 and C548 most for overheating of the replacement HOT. Mag has more than one version of DX700T, so component values can't be certain for all parts, without an FCC number, etc.

QUESTION NO. P115-9: Sony GDM1950 (also known as a HP A4033A) Monitor, the picture is running down from the top. I tried different frequencies but the running picture does not depend on these changes. The right Fix-Frequenzy is said to be 1024 x 768 @ 85Hz or 1280 x 1024 @ 75Hz. The signal itself is correct, I tried it with another monitor.

Some Sony chassis are identical among different brands, EXCEPT for the video input interface boards. The Sony GDM-1950 is single-frequency only, 63.34 KHz horizontal, 60 Hz vertical, 1280x1024 resolution; should support sync on green. The HP A4033A brand supports 20-85 KHz horizontal, 50-120 Hz vertical.

QUESTION NO. P114-4: Several Gateway CS1572 monitors take 5 - 10 minutes for the picture to come on. Went it does, the picture is real dark. The longer the monitor stays on the better the picture gets. After 10 - 15 minutes the picture quality and brightness are excellent.

If these are CS1572FS, FCC#IAW1572, check out cap C332 = 1000 uF/10V on the filament circuit. Also, remove any brown conductive glue you see, anywhere you find it, but especially check the CRT board near the wire for the G2, for this type of symptom.

QUESTION NO. P114-10: Two IBM 7097-5C3 monitors ans serial # 2304066. Q602 (C5442A) and Q607 (J449) shorted and R182 (I think it is 10 ohm 2 watt) was open. Replaced all, and set came up for about 20 seconds, then Q607shorted out again. Can make high voltage function by substituting B+ and base drive on Q602 with Sencore HA2500. With FBT isolated from B+, voltages on Q607 seem awfully high (around 200 volts). What should these voltages be, and what could be wiping out Q607? Also, what is the value R182?

Whenever Q602, Q607, and R182 are bad, C182 = 10 uF/250V must also be checked or replaced, it gets bad ESR and causes excess power dissipation. R182 = 10 ohm/2W.

QUESTION NO. P1028-6: CS1572FS monitor FCC ID IAW 1572, no video. There is High Voltage on the Anode. The CRT filaments are not lighting. Where is the CRT Filament voltage derived from? I checked the CRT with a CRT checked the filaments in the CRT are fine.

The Filament voltage (about 6.3V) derives from the the anode of D311 (negative polarity voltage), and is filtered by C332 = 1000 uF, which often goes bad, so check that cap. But scrape away any of that conductive brown glue, anywhere you find it, power supply, main board, CRT boards, it's nothing but trouble in this chassis.

QUESTION NO. P1027-9: Samsung Syncmaster 3NE monitor, when powered on a low frequency "click" is heard around power supply area. Power led and screen are off. When I disconnect it, frequency slows down until "clicks" stop. I checked power supply transistor and other components like diodes around it, even optoisolator and everything was ok. I replaced the horizontal transistor which was shorted, no change.

Check IC601 = KA3882 (an upgraded UC3842, like the Unitrode UC3842A or Cherry Semi CS3842B), and its associated components. Be sure the supply to pin #7 of IC601 exceeds 16V-17V for the IC's initial startup, and never dips below about 11V thereafter (even transiently, don't trust a DMM reading). If not, check components off of pin #7 (caps, diodes, transformer windings, start-up resistor values), or see if there is a short off the IC's output (pin#6). If good voltages to pin #7 are maintained, check for evidence of shutdown at pins #1 (under 1 volt) or #3 (voltage spiking above 1 volt). It is also a good idea to check all the caps in the power supply for good ESR.

QUESTION NO. P1027-2: Apple Multiscan 15" monitor has no red. I checked driver transistor.

A "Multiscan 15" might be several chassis, but if this one is M2943, the CRT board has been a big problem for loss of colors. The usual cause is very poor solder, all over the board, and the whole board should be reflowed; double-check the re-solder on the black coax jumpers.

QUESTION NO. P1026-6: I need an ECG replacement for C5339 Toshiba High Voltage of Monitor Acer.

2SC5339 is a 7 Amp transistor with internal damper. It is often unwise to try ECG subs for these types in monitors, and MCM (800-543-4330) and B&D Enterprises (800-458-6053) both list 2SC5339 in their stocks, but if you're insisting on an ECG, you might try an ECG2353. No guarantees, though (and, not knowing which Acer model it is, how could there be?).

QUESTION NO. P1022-1: AcerView 76E 7276e Monitor. I need a cross reference for a transistor location Q301 part number reads H8 S S 89.

Transistor Q301 is a BSS89 F.E.T. made by Siemens or Philips. The Philips device is available from Newark Electronics, among others. You should also check the following components Q382, J013 (picofuse), C327 (220pF @ 2KV, the original cause of the problem), R326, R241, R328, and R329.

QUESTION NO. P1020-3: Sony CPD-1791 monitor sometime ago displayed hourglassed image when switched on, then turned normal after some minutes. Now the image on the screen remains constantly hourglassed. I changed the IC TEA2031A, with no result. It seems the image can in no way be modified by the controls (?) RV251-252-253-254-255-303-304-305-306 on PBG626-5 board.

Also check all the SMD electrolytics on the daughterboard for bad ESR, but don't stop there. These caps will sometimes leak fluid that can eat traces and vias underneath the caps. Often it is hard to see this without magnification or removing the caps. Depending on what gets eaten, you get different symptoms. If any leaked, jumper any damaged traces and through-hole vias, and clean the board really well, besides replacing the caps.

QUESTION NO. P1019-7: Sun/Sony GDM-20D10 with bad pincushion. Remote control has no adjustment mode for this.

Check/replace all the SMD electrolytic caps on the DA daughterboard, often several are leaky or have bad ESR. To remove the daughterboard, you need only unsolder the four larger pins holding the board in place (one at either end of CN01 & CN02), then it should unplug. Also, check IC103 = DAC8840FS (Sony part# 8-759-041-45), and IC02 = -5V regulator.

QUESTION NO. P1018-3: Several IBM G50 6543-301 monitors that are dead. When turned on, they make a high pitch grumble. I suspect the flybacks are bad. I cannot locate replacements. It is a Sampo FEA-426.

Possible sources might be Component Technologies (888-359-2225), ICM (800-748-6232), Cactus Technology (626-357-7979), or Sampo itself, (770-449-6220). In Europe, try ICHE (UK), or AGEA Technologies (France). Or, for a substitute, HR Diemen (www.hrdiemen.es), email (HR@hrdiemen.es), lists their transformer# HR7933 as an equivalent to FEA426. Other components implicated in "dead" G50's are, capacitors C162 & C164; the AC bridge rectifer (BR66) and the two 1.5 ohm resistors beside it; R507 = 470 ohms & R523 = 1 ohm near the flyback; Q520 = ZTX948, Q521 = ON4873, Q522 = BUZ11A; the Z200 uProc.; and the front panel keypad.

QUESTION NO. P1014-1: Mag DX17F, the HV has self-imploded, as I see from a lot of reading this monitor seems to do on a regular basis. Could you tell me if MAG-INNOVISION Offers any help that you know of for this rather expensive lemon? I have several lists of components to check, just started looking. R177 and L105 are gone. I am sure the High Output Transistor is gone and one on the driver board also popped as I was inspecting it. Is it worth contacting Mag Innovision for their Upgrade? Funny, that word makes it sound like a recall and they will pay for the damage their poor design has caused.

First, there is not really an "upgrade" for the DX17F, just a standard set of parts that die or get degraded, and need checking, when any individual one goes. It would be unusual for a manufacturer to consider that situation 'poor design'; there isn't one component dying fast, it's just that a fault kills several of them. The owner of a DX17F might consider them a 'lemon', but for repair techs, they should be considered more like 'bread & butter'-- a common failure, with a defined solution, and a manufacturer that is actually willing to sell replacement parts reasonably. I'd take this Mag over a Nokia, Capetronics, Sony, or NEC chassis with the same symptoms, anyday. Once more, here's a basic list C120 & C123 (both 1uF/50V); R177 = 1 ohm, R181 = 120K; Q116 = IRF740 or 2SK1378 (depending); HOT Q109 = 2SC4747 or 2SC5048 (depending), D116 = 30DF6 = FR305 or ECG580. L105 is obtainable from Mag itself (p/n# T*I-281-103-UO), or from several parts suppliers, such as LJ Enterprises, Nationwide, MI Technologies, CCS, etc. Once in awhile, the flyback is bad; bad solder can occur, and other components occasionally do go bad as well, besides the basic ones.

QUESTION NO. P1013-10: KFC CB1414 VS monitor is totally dead. Tracing through mains in circ I come to a component which looks similar to a small relay. It has 3 terminals and is made of 3 copper contacts with 2 discs sandwiched between them. I 'd guess it's some form of diode arrangement. I have not come acroos this type of device before and need advice about what it is. It is just before the bridge rectifier in the main 220V line.

See the answer for question P923-7, about a similar device in a Proton monitor.

QUESTION NO. P917-6: GVC m1448b monitor manufactured in March 1995, when it is first turned on it is fine then over time it loses color and everything turns reddish or darker colored.

This sounds like a thermally-bad LM1203 chip.

QUESTION NO. P108-2: IBM 6321-001 monitor. When powered on it emits a pulsing squealing sound every second or so. There does not appear to be any high voltage. The power light does not appear to come on. I have checked most of the diodes / transistors in the main power circuit. I also checked the HOT on a whim. The HOT seems to have some funny readings.

It did turn out to be the HOT transistor that was blown. I have since replaced it and the monitor is now repaired.

QUESTION NO. P922-10: Gateway cs1572fs monitor. Q115 burst and R186 burned, need values.

The schematic is too blurry to read the exact value of Q115, it looks like 28665 or 28886 or something close to that. The value of R186 is 100 ohm 5W.

The transistor markings(Q115) are as follows: Top line is "T", middle line is "A1306B" bottom line is date code or something. R186 is 100 ohms 5watts.

QUESTION NO. P108-7: Two NCD 2082BA monitors have same symptom, scroll back 1/5 of the display, the 1/5 size of vertical at bottorm no light. I changed the TDA8172, and checked many caps, no change. Do I need to change the TDA9102C? I adjusted the vertical linear and center resistance, no change.

Check the FCC#, and you will see that this is yet another of those KDM2077 chassis. Pay special attention to caps C949, C950 = 100uF; they can cause vertical foldover even though they are in the power supply. You might also check out the 600-series 1 uF caps-- C609, C610, etc.

QUESTION NO. P108-1: J'ai des probl幦es de G1 sur un Sony CPD100sx; impossible de r嶲ler la lumi廨e g1=-174v.

Examine R545 = 2.2 megohm resistor, localized near Q507 on the CRT card.

QUESTION NO. P917-8: HP D2804 monitor equipped with crt Samsung M34KUN35X03. Is it possible to substitute with Toshiba M34KQA23XX06?

I save all the picture tubes from monitors I junk out, and substitute freely. Since the convergence is nearly impossible to set up, I leave the yokes on the tube. I can usually lay the chassis on its side and connect up the anode, yoke and ground wire (don't forget the ground wire!) without having to do the whole swap until I can see if the yoke is compatible with the existing drive stage. Surprisingly, about 75% of the time the tubes present no problem and the swap is relatively easy.

QUESTION NO. P922-5: MAG Tech DX17F monitor. In the process of performing the recommended horizontal circuit upgrade for the DX17F, I found that R177 original was .1 ohm, while the faq refers to R177 as 1 ohm. Is this an intended modification?

My schematic lists R177 as 2.2 ohms. It is just a surge protection type of arrangement, and the value is not critical. Be sure to check/change L105. If Q116 was shorted, it is almost certainly fried.

QUESTION NO. P922-4: PB 1512SL Monitor, FCC H4ICM15006, constantly switches between Normal and Standby mode (continuous clicking of RL401). Checked TP001 for 23.5V and Q424.

Almost all the problems these monitors have are caused by the Zilog IC in the front corner of the board going bad. Sometimes the little 8 pin eeprom next to it also goes bad, but I usually try just the Zilog IC first. I'm pretty sure static from the picture tube is what pops these, so I have gotten in the habit of putting a brass shield on top of them and grounding it. I have never gotten one back when I do this.

QUESTION NO. P923-7: Proton PM-1440 (fccBJNPM1448) no power indicater LED, completely dead. Fuse good,curious about square black component looks like relay, but has grey/silver discs inside seperated by terminals that are solder to pcb.

The black rectangular relay -looking box with the disks in it is the degaussing thermistor. It is designed to conduct a lot of current to the degaussing coil for a very short time when power is first applied. The disks will heat up very rapidly, causing their resistance to increase to the point where most current will stop flowing in the coil. They normally will be hot after a few seconds.

QUESTION NO. P930-3: Mag DX1795 Monitor FCC IAWDX17FG Power light, no video, no HV. Tested FBT & Q504 both OK. Voltages marked on PCB under daughter PCB + & - 12V & 5V OK, 32V = 1.1V.

I do not see any reference to a 32 volt line on the schematic. There is a 42 volt source which feeds the flyback/HOT that comes off D314 in the power supply. Do you have this voltage?

QUESTION NO. P106-7: DEC VRC20-HA Digital 20" monitor FCC ID ARFKDM2077 made by Sampo corporation model KDM 207 has full brightness. Brightness control has no effect, contrast works and the screen pot on the LOPT does adjust the intensity of the background. Checked HV 26Kv G1 and G2 are ok. Power supply voltages are OK.

Check the capacitor (C409?), 2.2 uF/250V, near the LOPT. If bad, it causes this symptom. Also, it is advised to check for other bad caps, especially C943, C944, C949, C950; these must be in good condition (low ESR), or there will eventually be trouble.

QUESTION NO. P105-8: Several Philips 4CM4270 monitors with the same problem. Replaced a defective H.O.T (BU2525) and the +B supply reads 90 Volts instead of 145 Volts. H.O.T becomes hot, no picture.

These Philips chassis do not shut-down when the HOT shorts. Instead, they drop the B+ voltage down. Running like this with a shorted HOT, will damage coils, locations like 5601, 5604, 5613, etc, so check those coils. Sometimes, some resistors also get damaged. The usual cause of the HOT originally shorting, is bad solder on the horizontal driver transformer, so also check the transformers out.

QUESTION NO. P104-6: Daewoo CMC-1501BA1 monitor with vertical problems. There is only a white powerful line on the screen.

Start by checking/replacing the vertical IC, TDA1675A, and the components associated with it.

QUESTION NO. P930-6: MAG MX15F monitor. Changed L505, C330, C332, C333, C542, R55, D503 (all new parts). Monitor now takes 3-4 minutes warm up to display an image. It will not start horiz unless it sent an 800X600. Once warmed up on 800X600 (5-10min), I can then switch it to any frequency.

Check for conductive brown glue on the logic board. This can cause many such weird symptoms. Fastidiously scrape off any such glue that you find there. Also remove any glue in the power supply as well, it will cause problems there too.

QUESTION NO. P98-5: Apple Multiple Scan 17" M2494 monitor. When brightness and/or contrast are increased, colors diverge horizontally, with green being the most obviously out of line.

Possible the crt is weak; blooming? Convergence should track as with B/W [purity]?

QUESTION NO. P101-10: Proview PV-8500 monitor FCC ID# IJEPV-5640. No picture, no LED and just a ticking sound from the board.

Some of these have that brown glue that gets conductive with aging, and causes such problems on the main board, so remove any of that you find there. After that, go to standard troubleshooting. Check the 3842 IC's circuitry and the associated switcher FET, and check out the horizontal components (HOT, FBT, CRT, etc). If the CRT is a Samsung tube, check if it is bad first, before investing $$ in a repair.

QUESTION NO. P101-2: IBM 2124 monitor. When switched on, sometimes a display is shown on the screen. I checked for bad contacts. The led on the front is green all the time.

Replace ceramic disk cap C335 = 220pF/2KV (it is better to use a 3KV-rated cap), also check the in-series resistor R214 = 15K ohm for damage. Do this soon, before this cap causes your HOT to short out. After replacing C335, run the monitor awhile at a faster scan rate (like 54 KHz), and then check if the new cap has been overheating. If it is overheating, the replacement cap is not of sufficiently high quality.

QUESTION NO. P930-8: Samsung syncmaster 3 monitor. Sides permanently curved in and cannot adjust (pincushioning).

Change caps C207 and C208, and check caps C206, C210, C211, C280, C301, C302, C307, C316, and C414; also check out IC201 and IC202. Due to a marginal original design by Samsung, C207 should be upgraded from 0.47 uF to a 1 uF/50V value, and install a 1 Megohm resistor between pin 3 and pin 5 of IC202.

QUESTION NO. P930-4: MAG dx1795 monitor lost control of pincushion and trapezoid, screen is hourglassed but otherwise good picture and full control of other parameters. On-screen values appear to adjust appropriately, but no actual adjustment occurs. Advised by Maginnovision support to check Q516 and IC701. Q516 appears good, do not have pinout for IC701, so I do not know where to verify signal when adjusting pincusion or trapezoid settings.

IC701 is TDA9103 (ST Microelectronics), get its pinout & electrical specs from the PDF datasheet at www.st.com/stonline/books/pdf/docs/1845.pdf.

QUESTION NO. P930-1: Two common problems with Sun/Sony GDM 20D10 monitors - first, horizontal jitter causing fuzzy image. Second, pulsating parallel vertical wavy lines, which do not cause any picture distortion. Both problems originate in the video board and tend to moderate after monitor is warmed up, but I have been unable to track down the cause with freeze spray.

On these units, check/replace ALL (26-29) the SMD caps on the DA daughter board. Avoid heating or yanking on these SMD caps, twist them off instead, gently twisting back & forth, or the adhesive underneath may rip out PCB traces. Use high-quality replacements, the problem these SMD caps usually get is bad ESR. To remove the daughter board, desolder the four larger connector pins, one found at either end of both connectors CN01 and CN02.

QUESTION NO. P929-5: AcerView 7176ie monitor. When turned on there is fast clicking and blinking power LED on the front. Q306 was completely shorted. I am having trouble finding a replacement transistor. The case has C5048 on it. What caused the transistor to blow?

The transistor you are looking for is 2SC5048. It is listed in B&D Enterprises catalog, 1-800-458-6053. For the cause check surrounding diodes and capacitors.

C5048 is a Toshiba 2SC5048, a 1500V, 12 Amp HOT. Try B&D Enterprises (800-458-6053) or MCM (800-543-4330). In this situation, always replace cap C307 = 1 uF/50V and ceramic disk cap C320 = 100pF/2KV (it is better to use a 3KV rating); these caps, even if marginal, can cause the HOT to blow. Also check D308, C315, C353, C3950, C3951, C3952. If problems persist, check the coils (L304, L306, L307, L308, etc), check for bad solder in the horizontal area or on the connector pins for the video amp board.

QUESTION NO. P928-4: Gateway dx17 monitor with an arcing crt base. Burned Q906, R909, R910, ZD901, D903. What are the values of r909 and r910? Also what is the equivalent of q906 k526? Any other parts which could be smoked?

You did not say whether your "DX17" is DX17F, or DX17S, etc, but if yours is a DX17S, see Monitor Repair Question# P97-5 and its answer. Still assuming this is a DX17S, to see if the arcing is a bad flyback (more likely) or a leaking CRT, try disconnecting the socket from the CRT, and see where the arcing now occurs-- CRT, socket, or board.

QUESTION NO. P927-4: ASTVision 7N KD-1711 monitor that has resistors R907, R915 and R916 burned beyond recognition. I suspect the flyback is the cause but the label on the FBT is worn.

R907 = 10K, 1/2W; R915 = 180K; R916 = 100K. You may also want to check C821, C901, D806, and Q904. For the flyback information and source, contact Korea Data Systems (they made this chassis). KDS's Tech Help phone# is 800-283-1311. You should refer to your monitor as a KDS KD1710 chassis (EVOKD1710).

QUESTION NO. P924-8: Gateway 2000 Crystalscan 1024NI Monitor only works at 640X480 60Hz. All color depths function at this resolution and vertical refresh. At higher resolutions or vertical refresh rates, the screen becomes garble and emits high frequency sounds from the monitor.

Some older Gateway chassis that read 1024NI on the front will only run at 640x480 and 1024x768. Other modes are not provided.

QUESTION NO. P922-6: NEC Multisync 5fg JC-1741UMA monitor operates normally with sync on green. With separate sync, modes with horiz. freqencies less than approx. 35kHhz are not recognized. Have substituted new control PCB, with same result. Appears to be problem with sync selection processing which is located on video PCB (inaccessible when control PCB is installed).

After obtaining schematic of video PCB, was able to trace problem to defective capacitor C8H2, 4.7uf 50V electrolytic, which had decreased in value. This, along with very high ESR, prevented it from coupling discrete horizontal sync to the input of sync processor chip, IC8G3 (except at high horizontal frequencies).

QUESTION NO. P923-10: IBM 6317-001 monitor with vertical problem. The picture only moves from the bottom not from the top,whereas it should move from the both ends by using the vertical controls. If the vertical button is pressed to open the picture, it starts shrinking the picture and work opposite of its function.

Try checking capacitor C311 = 10 uF/100V, near the flyback.

QUESTION NO. P922-3: CM-335 monitor, when powered on, the horizontal circuit starts but then it cuts off. The Horizontal Transistor it was subst.

If the horizontal output transistor (H.O.T.) was replaced, was the 1 Amp pico-fuse in the B+ line also open? Usually, the 10 uF and 47 uF capacitors beside the horizontal drive transformer (T401) also need to be replaced, when the H.O.T. is blown.

QUESTION NO. P922-1: Daewoo CMC-1427X1 Motitor, the screen rolls unceasingly on all sides like a disorder of vertical hold. I resoldered without success.

See if the vertical signal is entering (pin#4) and leaving (pin#6) of IC302 = Daewoo DW0158-xxx IC. This is a custom function control chip; if you need one, try NEI, 888-634-7278. If IC302 is OK, check out Q401, IC900, and IC401 (vert. input, pin# 5).

QUESTION NO. P910-1: IBM 8517 monitor works for a while then shuts down. When I turn it off, wait a few minutes turn it back on it would come back on. Did this for awhile, now it will not come on. High voltage just starts up then the high voltage goes down. Changed a few caps in the power supply. Sounds like the monitor is going into shutdown.

Check whether D503 (SMD zener, 9.1 Volt) has gone bad. If bad, replace with either an SMD or thru-hole type zener; zener voltage ratings from 9.1 to 12 Volts should work OK as replacements.

QUESTION NO. P98-9: Apple 1710 monitor, where the brightness is to high with retrace lines and cannot be turned down.

Check resistor RCB1 near the EHT. 10 ohm 1/4W. I had a similar fault, and replaced the flyback before I discovered the resistor.

QUESTION NO. P921-9: Mitsubishi HC3905 monitor which appears to have svga input in addition to rgb. If this is svga how do I get it to sync properly? Does it require a special card or is there some way I can change the setttings so it will work at standard refresh rates?

Mitsubishi monitors like this one use a 15HD video cable with a different pin-out from usual, for the inputs into the monitor. Using a typical SVGA video cable will not let it sync properly. For the special Mitsubishi pin-out, see the Answer to Monitor Repair Question # P827-9.

QUESTION NO. P920-1: Smile 17" monitor, screen does not light up but does crackle after LED goes inactive. Green active light comes on at power up then goes inactive (orange). A relay clicks back and forth on power up.

I encountered the same problem on a Smile monitor FCC ID# GBVCA6736DS which is actually made by "Kuo Fung". This thing is a bear to find exact replacement parts! The problem was originally damper-D104 by the HOT being shorted. I could not find an exact replacement, so I used a FMC G2C. I also found R111, and C125 out of value. As well L102 was leaking.

QUESTION NO. P915-4: Suntomo DB-1765 BA monitor FCC ID# H79DB-1765. Unit was struck by lightning. Q101 reads low Ohms on all tests, R101 is toasted. I need the value of R101. Looks like a fuseable 1/4 flame-proof. CR101 tests okay as does NTC101. Anything else to look for?

R101 is a .22 ohm resistor. Double check Q101 to make sure it is good.

QUESTION NO. P914-7: NCD NC2082BA monitor, with (possible) FCC ID LANGF010108M (I've tried this number through the FCC with no results.). The monitor initializes, i.e., the LED indicator turns from blank to yellow to green. The display shows a video pattern with low contrast (the imagne is covered with white fog). The screen then begins an intensity oscillation, from foggy display to black. With each oscillation the intensity of the display increases (the foggy apperance remains, but the display gets much brighter with each oscillation); this continues until a vertical white line is displayed. The unit then fails; and, the power supply begins to cycle. When I check the HOT; it is shorted. Note I checked the HOT prior to "power on", since many of your submitted problems were associated with shorted HOTs, and discovered the existing HOT was shorted; I replaced it with the OEM Phillips part, BU2527AF, which allowed me to discover the outcome of this behavior, a shorted HOT.

I don't believe that is the true FCC#, I think it is probably FCC# ARFKDM2077, (mfgr. Sampo), and the HOT BU2527AF will be Q730. With the HOT shorted, also check FET Q714 and ultrafast diode D719. This model is notorious for getting many bad electrolytic caps in the main boards and the power supply; often, over a dozen can be bad or marginal in one unit. For that oscillating display problem, I'd first check the caps in the deflection area, replace any that are marginal or bad. Also carefully check all the caps in the power supply. You probably should just replace caps C943, C944, C949, C950. These four caps must be in pretty good condition (low ESR) for the monitor to behave well. There will likely be more bad caps too.

QUESTION NO. P915-8: DX17t II monitor powers up with green light, no hv. Replaced D101 which was shorted. B+ reads 180 v, HOT tests good, good signal to HOT, no b+ to HOT.

Besides D101, also check/replace C548, and R173 = 1 ohm. Other suspect components are C117, R212, D109 (Schottky), L105. Also, note that Q106 in this unit occasionally fails with resistive leakiness, not with a complete short.

QUESTION NO. P915-9: Sony CPD-15SX1 monitor. Switching power supply does not work, no signal to the gate of power FET(Q6) from IC-2 (uc3842AN). The Vcc of IC-2 is ~3.5V. The relay "click" one time as the power cord plugs in.

IC2 (UC3842AN) requires approximately 16 Volts VCC on pin #7 to start. VCC is usually supplied from the raw +160 Volt primary (line-side) supply via one or two large value dropping resistors. A zener may also be used for regulation. After the supply starts, the VCC is supplied from a diode-isolated low voltage souce via a power transformer secondary winding. Try lifting pin #7 of the IC & check the VCC. If it rises to normal, the IC likely is bad. If it remains low, look for series resistors that have increased in value, a filter capacitor that has decreased in value or with high ESR, or loading components such as a zener or isolation diode that is leaky. It is important to monitor the VCC at the instant of turn-on. If the supply actually starts momentarily and the chip shuts down due to an overcurrent condition, pin #7 will be pulled low & latched by the IC itself until power is removed. If this occurs, troubleshoot the loads on the secondary of the power transformer.

QUESTION NO. P914-4: Xyst 14" Monitor. Horizontal line appeared in center of screen suddenly. Changed TDA1175 to TDA1175P, no results. I cannot find TDA1175, so substitute with TDA1170N, View restored but picture shrink to only half of normal screen. Are TDA1175 and TDA1170N changeable? If not, where should I modify it so I can use TDA1170N and get back my full screen view? I cannot get TDA1175 in the market. I tried to use TDA1175P but cannot.

TDA1175 is available from LJ Enterprises (800) 627-8755, however TDA1170N should work as a sub in most instances. Check all electrolytic capacitors in this circuit for high ESR, particularly the cap connecting pins# 3 and #5 (usually 100uF). This is likely the cause of your problem.

QUESTION NO. P910-9: Hewlett Packard m#a4033a monitor with a R858 in the the power supply that is burnt beyond recognition. It looks like it is a protection resistor for the horizontal driver and output (both are bad). I need the value of this resistor.

H-P A4033A monitor is actually a Sony GDM-20E01. R858 is not a valid location number. Sure you don't mean R588? R588 is 10 Ohms 1/4W flameproof.

QUESTION NO. P99-6: Dell D1028LR Color Monitor ( Phillips Manufacture Chassis CM 6800). Problem Horizontal collapse, thin line down centre of monitor). I have checked for dry joints on scan coil connectors etc & continuity of the coils themselves. I replaced Diode 6632 which was short circuit (BYV 36C). This was in the scan circuit, however on switch on it has made no difference.

According to a technical bulletin from Philips, check R3550 if open perform the following: Replace- R3550 1.5ohm 1/4 w 4822 052 10158, Q7520 mtp6p20e 4822 130 63882, Q7630 BU2527A 4822 130 63627, add Q7523 4835 130 47173 (grid c-12 on schematic,CBA prescreened and drilled), remove choke L5502, remove jumper 9605 (grid B-12) and replace with a 1ohm resistor 4822 052 11108, add 220ohm (4822 116 83872) from collector of Q7518 (grid D12) to jumper 9128 (grid F8). This is the second bulletin (and most recent) for this problem. Grid numbers refer to grids marked on the schematic. Philips service manual number 6595.

QUESTION NO. P99-7: Magnavox 20CM64BE01 20" monitor with a damaged main sweep, & high voltage module (flyback mounted on this module). Some of the damaged components were burned beyond identification. I need the part number for the main sweep & high voltage module in this unit & a source for replacement. Possible part number on the board is 3138 108 82880. I also need the part numbers & values of the following parts also on the same module board for this unit. Coil L 5604, Resistor or Coil 3473, & Var Resistor pot 3660.

For a parts source, try NAP (Tennessee), 800-851-8885, they can also ID parts; I found out that coil #5604 is Philips part# 482215763218 (assuming that your unit's FCC# is A3KM020, too...) If they can't ID those parts for which you do not have the location numbers, try the Philips tech help line, 900-896-8324.

There is a sevice bulletin from Philips concerning problems on this board and it sounds like it might be what you have. If Q7605 and/or Q7615 shorted do the following: replace Q7605 with BU2527 4822 130 63627, replace Q7615 with BU406 4822 130 47377, change C2609 to a 5.6nf 1.6kv 4822 121 43677, change C2608 and C2610 with 4822 124 22676, change D6608 EPG30G 4822 130 83128, add a 33ohm 3 watt resistor in parallel with R3655, replace C2607 with 4822 124 42161, check and replace L5604 (usually burned) 4822 157 63128. This was a common problem with this set when it was current. Phillips issued several bulletin until it finally came up with this mod. Once done, set does not return. Service manual number 6562.

QUESTION NO. P99-5: Acer 54e monitor, the failure led flashes intermittently. K2161 blown and when it is replaced and the board is turned on, there is an acute tone that lasts about 3 seconds and then the led starts flashing intermittently and the K2161 is blown again. Tested the c335, all diodes, transistors and caps around and the hot too and none seems to cause the failure.

If the FET is blowing, check if L304 (2 mH) has any shorted turns, also see if rectifiers D316 & D317 are at all leaky, not simply shorted. The original culprit for many of the problems on this Acer is frequently C335 = 220pF/2KV ceramic; replace it if is at all discolored, or gets warm running, or even on suspicion. This cap can seem to test OK, and still do damage to several components. Its series resistor, R214 = 15K ohm, sometimes burns also.

QUESTION NO. P97-6: Radius 0461 monitor FCC # AK8GDM20EO1 is shutting down on startup, with power and power save leds flashing but this time it is the geometry led that is on steady. What does this fault code mean? I have not found any faulty components yet but from your previous answers, I have now replaced or checked all the suggested components ( Qs , ICs, Cs, Rs and fuses ) without effect.

The GEO light being on, indicates a high voltage failure. If all the FET's, HOT's, and the microfuses were all OK, then the usual problem on these chassis is a bad flyback transformer. But sometimes it is IC801, a 4049B CMOS logic IC, that is bad, and since that is slightly cheaper, check that first.

QUESTION NO. P97-5: Gateway 2000 DX17S monitor FCC# IAWDX1768SL. Symptoms; q906 irfi630 , diode d903 5d150f & zener zd901 all s/c. What is the value of zd901 it is labelled as 12a2 ( 12v??)? What is the normal b+ on the HOT? Are there any other components likely to have gone?

ZD901 is a 12 volt zener. Besides the parts mentioned, check out the CRT, and check FET Q511, transistor Q512, and signal diode D527. The flyback may be bad, but sometimes rings OK despite this. Check for evidence of arcing at the CRT socket, and between the H & V focus wires. It is important when adjusting H & V focus pots, not to let the differential voltage between them get too large, or arcing may occur where the wires come close. Q512 should drop its 185V, to about 168V on the drain of Q511. Q906, the regulator FET for the HV generator (Q903), should regulate the B+ voltage at the FBT to about 48VDC at 640x480, 78VDC at 1024x768. The source of Q511, the FET regulator for the deflection HOT (Q503), should be at about 63VDC at 640x480, 98VDC at 1024x768, when it has that proper input voltage of 168VDC at its drain.

QUESTION NO. P93-7: CTX VL700 monitor that has excessive brightness & brightness control has no effect. Screen control has no effect either. Have checked cap & resistors in Hi Voltage area with no luck.

Check out Q336 = Philips JC337-25, signal diode D306, and 12V zener ZD402 for shorts/leakiness, and R480 = 240K, for value. The screen control on the flyback is nonfunctional, anyway, by design.

QUESTION NO. P93-5: Mag DX15T monitor. I changed a shorted Hot (2SC5129). Over components around that TX mesure OK passively. It works but after about 10 minutes, it seems to get hotter then usual. Is it normal or is there some over marginal component (s) that strains it?

Ring out coil L105. This coil is NOT the same Mag part# found in the Mag DX17F; Mag Innovision's (800-827-3998) part# for it will probably be LL*-31L-4LO-*A LSE.

QUESTION NO. P93-2: Qvision 200 monitor, dead. The first message was HV failure. I found C839 burnt up and a 330k ohm on the back of the board bad. I replaced both and now it comes up with V out of sync or H out of sync. It sounds like the HV is coming up and then dies at start up.

This is a Philips/FIMI chassis (FCC# GZM). First, bad CRT's can occur, and should be checked for first. Then, besides the parts you replaced, carefully check out the three blue 1.6KV film caps, and also V805, V851, and V852. Best to replace with the Philips' originals, not with subs. Note, the BY584 high voltage diode has a substantial V-forward, so a good diode may well test open on a DMM's diode tester. If the HV failure persists, it's probably the flyback, possibly the focus module. There are three versions of these, depending on which CRT is fitted, so be sure to obtain the same number.

QUESTION NO. P92-10: IBM 9527011 monitor. We have replaced R143 which was open, as well as T26, T32, and T47. T26 showed signs of excessive heat. We have B+ voltage (160V) but it does not appear to be making it to or through the horizontal circuitry. The B+ is making it to C96.

If you check the FCC number, you will see that this is a Nokia chassis. Check that those FET's are getting good gate pulses. Also, inductor M3 can cook and short between windings, so check out M3. You may need to change the TDA4852 on the microprocessor board. This Nokia has the same problems that other Nokia chassis have (bad solder, bad SMD's, etc); see more details in Monitor Repair Answer# P826-1.

QUESTION NO. P92-9: Packard Bell 1512sl monitor has vertical frequency of about 20Hz. I changed IC TDA9102C and Z0861404PSC, it did not help. I think that IC 93C56 needs to be replaced, but I do not know what program.

It sounds like your particular 1512SL is the Lite-On chassis, FCC#H4ICM15006, not the Goldstar. You buy preprogrammed Eeproms (I703 = 93C56) for these Lite-On's. A good source is LJ Enterprises (800-627-8755); other possible sources are Nationwide Electronics, or CCS/EDI. Sometimes, I702 = MTV003 also dies, when I701 & I703 both go. It is a good idea to put a grounded copper shield on top of that new Zilog chip.

QUESTION NO. P92-5: Sampo KDM-2077 monitor has foldover at the bottom of screen. Top of screen is fine. Checked all caps and replaced TDA vertical IC.

This chassis is notorious for large numbers of bad or marginal electrolytics. Do a complete cap check, you'll probably find several dead, and a dozen or more on the edge. Some, like C943, C944, C949, C950, can quickly do widespread damage even if slightly marginal, and probably should just be replaced. For your immediate problem, try cap C609 = 1 uF/250V, but check the others, or it will come back to haunt you.

I have found that electrolytic capacitor c949 on the power supply board is the most common cause for this problem. This capacitor is used to filter the -16V supply which is used for the bottom half of the vertical deflection.

QUESTION NO. P827-1: PV-772IM monitor. The horizontal transistor C5251 was burned. I changed it, it ignites several times, but in one of them when extinguishing it, soon it does not return to ignite. One becomes to burn C5251. I also changed zener ZD601 and C616, but happens the same.

It seems to me that either the flyback transformer or all components connected to the horizontal output transistor are at fault. If you have a flyback tester like the one sold by Anatek, you may find out if the flyback is at fault.

In this particular monitor, sometimes, when C5251 repeatedly is blowing, using 2SC5207A to replace the C5251 stops that problem.

QUESTION NO. P823-9: Samsung SyncMaster 3Ne monitor, the horizontal size is too big. It cannot be adjusted with the potentiometers.

Very common problem with this unit. Check Q406, you will probably find the bad solder on its pins. if this is the case, you also need to replace D407. It may check ok but replace it anyway.

QUESTION NO. P827-2: Compudyne Kd1500N monitor April 94 factory ID GM, FCC ID EVOKD-1500N. Picture too wide H. position OK, vertical controls OK. H. size control (0-15K) works like a pincushion. Both pincushion, controls, 0-10K and 200-1200 ohm have negligable effect. VR611 adjustment does not help, nor does VR902. Replaced IC' 302 (ECG987) and IC602 (ECG7062) No change. All other connecting diodes, caps and trans. seem to be OK, except Q306, Q307 and Q308 marked C102, unable to identify do not measure like standard trans. Also, Ic's 303 and 902 are part of this circuity.

Check/replace high voltage (160V or 250V) cap C615 = 10 uF, coil L603, diodes D605, D606, and transistor Q611 = 2SD1138. It's also a good idea to check C624, C625, C626 for high ESR and value, besides C615. If one of the two HV caps, in series off the collector of the HOT, has shorted, this will give excess width, but also gives lowered HV and a dim display.

QUESTION NO. P827-9: Mitsubishi Diamond Scan HA-3905ADK Monitor. Read here that their Cable for Dell/Mitsu monitors is not a standard Cable like for VGA. Is that true for this model? I have been trying to align the picture to my test box, but it is all over the screen, cannot seem to sync.

Yes, this model uses a different cable pinout from usual, and using standard VGA cables does give that sync. problem. The Mitsu. cable's pinout, on the monitor side is, pin #2 = red; #3= red ground; #4 = green; #5 = green ground; #6 = blue ground; #8 = vert. sync.; #9 = horiz. sync.; #10 = blue; pins #1, 7, & 11 - 15 are no connection. The cable's pinout, on the computer side, is, pin #1 = Red; #2 = Green; #3 = Blue; #4 = ground; #6 = red ground; #7 = green ground; #8 = blue ground; #10 = ground; #11 = ground; #13 = horiz. sync; #14 = vert. sync; pins #5, 9, 12, & 15 are no connection.

QUESTION NO. P827-7: Toshiba version of this Gateway 2000 1572FS monitor has a black relay in right rear that clicks every one second or so after power up. Nothing on screen. Previously responded to flexing the main PCB. Found bad solder at Q105 but repairing this only made the problem unresponsive to flexing the PCB (?).

There are a couple FCC #'s for the 1572FS, so I am not sure which your Toshiba is, but, depending on the exact case used with the 1572FS, the plastic bottom can warp from heating over time, and plastic tabs protruding up from the bottom can hit the PC board in the monitor, mashing solder joints. This is especially true, for the tabs on the swivel base case. If this is the case, check and resolder the affected solder joints, and besides Q105, also check / resolder R302, L103, and the yoke connector. To prevent further solder problems, slice 1/8 inch or so off the plastic tabs at the rear. Also, if R331 = 91K is present in the power supply of your version, and is even a small amount high in value, this can cause problems. If it went open, that might even have killed the CRT. If replaced, adjust VR303 to drop 180V across R331. Other potential culprits are C116, C120, Q106, Q301, HOT, D107, ZD307, IC103, IC301, R179 = 20K; some of these also cause no HV, as well as no screen.

QUESTION NO. P89-9: Mag Innovisions NA0503-01 monitor that is exhibiting an intermittent green picture. Acts like a shorted CRT. Can a B&K precision model 470 be used to test and possibly rejuvenate this tube? I do not know which tube adapter socket it needs. The CRT number is M36EDR314X360/2F01 it is a Phillips tube.

Yes, B&K 470 can be used for testing , even rejuvenating if you are brave (Sencor preferred) shorts remove function seems to work well . There is an adapter for the B&K that uses clips but I forget who sells it . You can wire it yourself using old socket or such. Connect only one gun at a time using (most likely for your tube) pin 9 ,10 for filament , 8 for red cathode, 7 using red G2 , 5 using red G1 , just move cathode wire to 6 for green cathode and 11 for blue cathode leaving the rest alone.

QUESTION NO. P826-1: Nokia 447E090 monitor. Narrow vertical bar; rutured R195 & R205. What values are these resistors? What other damage should be suspected, if any?

R195 & R205 = 215 ohm, 0.5 Watt. In general (some part variations), on the several 447E chassis variants, when these two resistors burn, also check PFET's like T13 & T27, HOT T32, inductor M3 for shorts between its windings, resistors R120 = 100 ohm & R224 = 0.47 ohm, diode D28, & capacitor C121. Also check the various small SMD transistors, like T60 or T65, often marked '3F' = BC857B; these often go leaky or bad, but never it seems to be the same one twice. In the US, Trillium Industries (919-829-9747) carries Nokia coils; you'd need the coil's "FM" number, since "M3" is just a location. The Nokia chassis with thru-hole rivets should have any bad solder on these rivets resoldered on BOTH sides of the board; the bad solder is a common problem with these models.

Check transistor T24, a BF422C TO-92, right next to the TDA2040 amp.

QUESTION NO. P826-10: Dell P1728U monitor. It has a Mitsubishi chassis TB92108801.2. I replaced the shorted HOT and it worked for about 10 seconds until the HOT shorted again.

If you found the HOT Q503 shorted, what was the condition of Q534, the P-FET that regulates its B+? When this P-FET (usually a 2SJ307) goes, it overvoltages the HOT. Also check for any bad components (diodes, resistors, etc) off the gate of the FET, to avoid more blowups. If, when you say the new HOT "worked", you mean the unit powered on, but you didn't actually see a full display briefly, then it is also reasonable to check the horizontal yoke coil and/or the CRT for shorts as well. If you do need 2SJ307, you might try B & D Enterprises (800-458-6053) or MCM (800-543-4330).

QUESTION NO. P825-1: Xyst FM360 (18021-14021 Rev .06) 14" monitor. Vertical suddenly collapsed, horizontal still works. Changed vertical amp TDA1175 but no luck.

If there is still no vertical deflection after replacing the vertical deflection IC, start troubleshooting around this chip you should be able to trace from it to the problem. Are both the IC's power supplies (for the amp, and the output) present? Are any associated components bad? Is there a vertical input? Is there a short, or an open/bad connection or component, off the output or in the vertical yoke circuitry? Get the datasheet for TDA1175 from www.st.com/stonline/books/pdf/docs/1840.pdf The circuit diagrams and pinout should be a help in doing this troublehooting.

QUESTION NO. P810-2: Laser SVGA 14" monitor (Goldstar CA-14 chassis) with a horizontal line (no vertical deflection). I changed vertical IC TDA1675 to EGC1862, no change.

If there is still no vertical deflection after replacing the vertical deflection IC, start troubleshooting around this chip you should be able to trace from it to the problem. Are both the IC's power supplies (for the amp, and the output) present? Are any associated components bad? Is there a vertical input? Is there a short, or an open/bad connection or component, off the output or in the vertical yoke circuitry? Is there a high output at pin#13 that might indicate a bad yoke circuit? Get the datasheet for the TDA1675A IC from www.st.com/stonline/books/pdf/docs/1192.pdf The circuit diagrams and pinout should be a help in doing this troublehooting.

QUESTION NO. P823-10: IBM 6543-301 monitor (G50), dead. I have a 45vdc in the hot. In the power supply I have 166vdc. I changed IC tda4855 and tda4866 with no change. Also, what is the IC ST6370J5B1/BLI.for this?

If the unit is 'dead', check Q520, Q521, Q522, Q603, R102 & R145 = 1.5 ohm, R133 = 0.15 ohm, R424 = 180K, R520 & R521 = 22 ohm, R523 = 1 ohm, the bridge, CR113 = BR66, CR502 = BYV27, and check caps C162 = 470uF/25V and C164 = 1000uF/25V for value and ESR. These two capacitors, when marginal or bad, can cause a host of problems. That voltage of 45 VDC is too low. It could be there's a fault in the voltage boost circuit run by FET Q602, if the FET does not operate. It would be unusual (though not unheard of), for a FET to fail as nonfunctional, rather than shorted, so see if the FET's gate is getting good drive pulses. If not, my suspicion would be to ring coil L600, in series with the FET, for shorted turn(s), that would cause an overcurrent-related shutdown of the driver IC, Z600. But, there's a possibility that the driver IC could be dead, or that it's not receiving its 12V supply (at pin#7). The preprogrammed microprocessor IC, ST6370J5B1/BL, is an expensive and hard to find IC, that, when it goes bad, can cause shutdown problems.

QUESTION NO. P817-4: Sony GDM20SE1 FCC AK8GDM20EO1 monitor no screen, shuts down immediately after powered up. Power and PS leds flashing, center led solid. Any info on the led combo failure type?

In the Apple M1823, a related chassis, flashing power & power-saver LED's along with the CENT LED on solid, is a code to indicate a scan circuit failure. Check the HOT Q512, P-FET Q511, the various microfuses (PS500, PS501 = 1.6 Amp, etc). It is also advisable to check the electrolytics in the power supply main board for bad ESR, leakage, and value, most notably C611 & C612, and several 10 uF caps on the main board. Marginal or bad caps can overstress the horizontal circuit components.

QUESTION NO. P817-3: I need information on an IC (video amplifier) part number cva2411tx for a Hitachi computer monitor.

The CVA2411TX video IC is made by Calogic Corp, and you can get its specs and datasheet from this website www.calogic.com/crt_driver_amps.htm.

QUESTION NO. P816-4: CTX 17" CPS-1760LR monitor. Upon powering up, I receive four short clicks then it immediately shuts back off. I have narrowed it down to the power supply.

Check the following R109 = 56K ohm/2 Watt, C308 = 4.7 uF/250V, C403 = 22 uF/50V, and C135 [sometimes unmarked, 47 uF/250V, back by the 15HD video input connector]. Besides those, also check Q305 = 2SD386A, Q401 = HPA100, D410 = UF5404, and R353, which are also suspect in this situation, causing video problems when defective.

QUESTION NO. P813-3: In reference to question P628-4 on Mag DX17F, what is a known cross for Q107 (2SK891)?

2SK891 is nothing special; it is a 200 Volt, 18 Amp, 125 Watt FET. This can be readily subbed by IRF640 or BUK456-200 FET's.

QUESTION NO. P723-8: Mag DX17 monitor, brightness too high. Cannot back down enough with brightness control. I turned down "screen" pot on transformer, but brightness was back up again in a few hours. Now brightness control on front panel has little effect, but contrast control does.

You probably have an open resistor in your brightness circuit. (Typically a fairly high value, 100K to 1 or 2 Meg.) I have found this to be a problem on a variety of monitors.

QUESTION NO. P812-3: US Logic MM500 15" monitor suffers collapse & roll gradually after unit is at operatng temp. Only affects 800x600 and higher, Temp is the triggering factor. I am unable to isolate the specific component, however a fan aimes at front of the PS side of the main board will gradually restore the video within a minute or so. FCC ID HSUTRLDH-1570 US Logic cat32-10265 Jan 96 Ser# T131859

Monitors with that FCC# can get this problem from the TDA9103, a 42-pin PSDIP IC. Usually, the IC itself is bad, rather than associated parts, and must be replaced.

QUESTION NO. P723-9: Applevision 1710 M3525 monitor. After powering up, the monitor starts to tick (about 2 ticks / sec ), tube is pulsing in sync with the tick and the LED on the front does the same.

Sounds like a classic case of high voltage arcing. If you remove the cover and turn down/off the room lights, you will probably see a spark jumping inside the chassis making the ticking noise. In most cases, it is just a bad solder joint in the high voltage area.

QUESTION NO. P89-3: Mag DX17 monitor with a shorted Horizontal Output Transistor and VR501 Burnt. VR501 is a wirewound pot. What value resistance and is the shorted Hot the reason for its demise?

In the DX17S here, VR501 is a 100 ohm pot. However, Mag makes several different "DX17" chassis, including DX17F, DX17FG, DX17S, DX17T, DX17T-II, so your chassis may not be the same. Not knowing which chassis, I can't give any reliable information on the causes, either. You may wish to re-post, using the entire model number.

QUESTION NO. P89-5: Gateway 1776 dx17s monitor has about 1" horizontal collapse on the screen. The width adjustment does not have any effect at all, the vertical is full screen and has adjustment. I have checked all the dc voltage that is marked on the main board. Is there any factory service menu to check values in the eeprom?

Check out Q511 and Q512. I suspect Q512 is dropping excess voltage, leaving little left for the collector of Q503, the deflection HOT. If Q512 has excess voltage and is running hot, but is still intact, trace back from the base of Q512, checking D527, etc. But also check out D503 & D508 for leakiness, the TL082 & NE555 chips near the flyback, and the coils (L504, etc). Also, this model is known for having flybacks that seem to test out well by ringing, but are actually bad. You may need to swap it.

QUESTION NO. P89-4: Macintosh AKA M3502 21" monitor. Main deflection board went up in smoke, Horizontal output transistor shorted, R113 was open, R109 burnt up, and C106 burned as well. What is the value of R109? Anything else I should check to prevent reoccurrence of problem?

R109 = 22 ohm/1.6W; R113 = 10 ohm/3W; C106 = 0.0056 uF/2KV, 5%, polypropylene. With those bad, also check C108, C113, C116, C117, C121, C123, C124, C138; U101; V104, V105, V106, V107, & V108. Especially check diodes V105 & V106 for leakiness.

QUESTION NO. P730-9: KDS 1730 monitor, need info or subs for D805, D814. Both are marked S2L64, cannot find any info on them.

The "S2L 64" rectifiers are Shindengen S2L ultrafast rectifiers, rated 1.5 Amp (50 Amp pulse), Trr = 35-50 nanoseconds. But the "64" is just the date code, which probably explains the difficulty in identifying them. The COLOR of the band on the diode is used to identify the voltage rating red = 200V (type S2L20U), yellow = 400V (type S2L40), blue = 600V (type S2L60). S2L60 types (600 Volt) could be subbed by rectifiers like BYV27-600, RL4A, SF20J, UF1505 or UF2005; B & D Enterprises (800-458-6053) does list RL4A in its stock. If some loss of speed is acceptable, HER206 (70 nsec) might be tried. The S2L20U or S2L40 types might in addition be subbed by SF24 (200 Volt) or SF26 (400 Volt); Mouser (800-346-6873) and MCM (800-543-4330) list SF24, SF26, and HER206 rectifiers.

QUESTION NO. P730-5: Compaq Presario 14SV 475A monitor (FCC CSYSC-428PTJ) Total loss of sync. Sweep signals are extremely noisy. This can be seen both with the scope and on the CRT. Power supply filtering seems to be OK. High voltage about 22K. Have visually inspected solder joints and resoldered some.

A common problem is IC202, a 5V regulator, either having bad solder, or being bad.

If you have no Horz. sync and the unit has a squeal to it, check IC202 (+5v regulator) for loose solder. If the sync loss is vertical only, check solder connections on the video cable connector. Both of these are very common.

I submitted the original problem. The fix turned out to be replacing IC201 (SL606) which was available from Electro Dynamics Inc. Because of noisy waveforms I was seeing from this IC, I took a chance and tried this, with success.

QUESTION NO. P726-7: Tandy Cm-5 monitor which the end of the data cable has been pulled off. The circuit board is marked with the actual function of the wire but the color code and pin configuration of the end which connects to the computer are not there. The connector is 9-pin.

Borrow a book from the local library and lookup the pinout for the 9 pin CGA/VGA connector for the video output of the computer. Then wire the cable accordingly. Should be standard CGA codex.

QUESTION NO. P729-8: KDS 17" monitor FCC ID#EVOKD-1730. Resistors R901 R902 R904 burnt, need the values.

Your KDS monitor has the same FCC# as the VTC SC-7 and Princeton monitor for which these resistor values were given, in the answer to Monitor Repairs question # P728-9. Any chassis with the same FCC number are supposed to be the same electrically (under the law).

QUESTION NO. P729-7: Gateway 1572 monitor I need a horiz output trans labeled c5129 which does not cross in ECG.

2SC5129 is available from B&D Enterprises (800-458-6053) and MCM (800-543-4330), among others.

QUESTION NO. P728-9: VTC SC-7 monitor FCC ID# EVOKD-1730. Resistors R901, R902, R904 burnt beyond recognition, they come from ABL pin of flyback.

A Princeton brand unit, with that same FCC#, has R901 = 27K ohm, R902 = 12K ohm, and R904 = 12K ohm. Probably should also check R903, R919, R948, C902, D901, ZD901, Q901.

QUESTION NO. P728-7: DTK MD-1737 Monitor. The upper half of the vertical screen is missing. The lower half of the vertical is good. The horizontal sweep is good. The vertical output transistor is good. It has a TDA8351 does this IC control any of the vertical? Should I swap it?

Yes, TDA8351 is a vertical deflection IC, with a bridge-configured output stage at pins 4 & 7 (pin 5 = ground). If the IC's power supply and flyback supply voltages, at pins 3 & 6, respectively, are OK, then swap out the chip. That bottom-half-only picture is one symptom that does get seen with defective TDA8351 IC's.

QUESTION NO. P728-5: Compaq Qvision 200 monitor. Mainboard 82192533563.2 C839 has melted, I need the value for this component.

C839 = 470 pF/ 2 KV. Is R910 = 330K/1 W on the solder side of the board also burnt? Are those three blue 1600 Volt Philips capacitors all measuring in spec?

QUESTION NO. P728-8: Where can I buy a circuit board for an NEC 2143 monitor? It is the front panel control board<pwe-404b> or Q25-157MS. I am not sure which one is the part #. NEC will not sell to anybody.

Does not surprise me about NEC after what they have done to their consumer base. I'd contact their customer relations devision and voice my opinion to them about not supplying parts. They stranded millions of cunsumers when they dropped their consumer electronics line a few years ago. I personally do not buy any of their products due to these facts.

QUESTION NO. P727-10: Acerview 34e monitor Model 7134e. I found and replaced HOT 2508AX (shorted) and capacitor 221K/2KV near yoke plug. I hooked up the monitor and it worked for a few hours then the HOT shorts out again.

Besides the HOT and 220 pF ceramic cap, check the B+ regulator FET = 2SK2161 or IRFI630, located on the same heatsink as the HOT. It can get leaky, and deliver excess voltage to the HOT. Also see if R214 = 15K (in line with the cap) is OK, and check out the coils and diodes in the circuit upstream in the B+ supply.

QUESTION NO. P727-3: Two Proview pv1564 monitors, totally dead (no light in power on indicator), and the only sound I hear when power on is from the degaussing. B+ is 0V, but there is power on rhe FET in the power supply.

Is the FET receiving pulses at its gate from the 3842 chip? If not, check or replace the 3842 IC, check any diodes or resistors between pin#6 and the FET's gate, and see that the power supply is providing the proper Vcc voltages to the 3842 at pin#7 (on a scope, at least 16 volts for startup; not dipping below 11 volts while running). If the Vcc voltages are bad, check any resistors, electrolytics, or diodes off of pin#7. If the FET is getting good gate pulses from the 3842 IC after all, does its drain react to the pulses, or is it dead? Also, check to make sure that the current-sense resistor, in line with the FET source, is not open. This model is also known to develop bad CRT's, so if a new CRT would cost too much, check the CRT out first, before going further.

QUESTION NO. P78-7: Tatung 4524 15" monitor. If I change the graphic mode, the screen size changes and I have to manually adjust screen size. In DOS mode is working properly. I have doubt to TDA 9102C/T.

The same thing will happen with my digital monitor. Basically the problem is the video card. First make sure you have the newest drivers for your video card. Second, usually for new video modes you will need to set the video params manually. These settings are remembered by the monitor as long it is plugged in. If you use a surge protector to shut off everything it will most likely lose its information.

QUESTION NO. P722-4: Orchestra Monitor 15" FCC IDEVOKD-1510. I replaced a shorted HOT BU2520DF with a C3892A. Runs OK and transistor stays cool but scan is totally out of wack. Video much too dark, Horz width much too narrow and Vert scan way way too high. Able to get close with controls but not proper. Changing resolution throws all out of focus and much too bright.Would it be my later type video card?

Check out IC401 = STV7778, this IC controls both the horizontal and vertical scans, and the chip is prone to developing problems. You may need to simply replace STV7778 (or sub a TDA9103, if it is more convenient). Besides IC401, you may wish to check the solder on the flyback, and also the components C903, C905, C907, D902, D903, D905, Q407, Q802, Q902. Substituting a 7 Amp HOT (C3892A) for a 10 Amp HOT (BU2520DF) seems like a poor choice, and may cause early demise, of itself or of other components. Since BU2520DF isn't scarce or expensive, why not avoid any doubts, and go back to the original HOT type.

QUESTION NO. P723-6: Viewsonic 21PS monitor, the uprocessor chip is defective. I need the location number or an alternate source. Also, is the same chip on a 1782-2 ( Viewsonic 17") the same part? The motherboards of these two monitors are almost identical.

You can call Viewsonic at 800-888-8583 for ordering their monitor parts. For the part identification questions, email vstech@viewsonic.com.

QUESTION NO. P721-10: Je travaille sur un sony 17sf2 ou j'ai chang� q507=2sc3997, IC601TEA2262, Q602=IRFPC40, R602=0.22ohm/2W, Q503=IRFI9630 et Q510=FS10SM-18 Maintenant il d幦arre mais se met en power saving.

Examine D596, a signal diode near the flyback transformer, for excess reverse leakage. D596 is a common problem in the Sony 17SF2 chassis, and one can substitute almost any signal diode (1N4148, 1N4448, etc.). Other problem components to test are C525, C540, C541, C592, and IC904 = TDA9103. Because Q503 was defective, also examine Zener D505.

QUESTION NO. P722-6: Gateway CrystalScan 1024NI monitor, Ch#cs1024NI2 and FCCID#IAW. Replaced shorted HOT. D502 on M'Board was blasted, I need replacement ID#, please. (Subbed a best guess diode and set ran for 2 minutes, then subbed diode shorted out.) All other static tests appear OK. Any other chronics I should know about this chassis?

If the OEM D502 was marked 15DF, it is a fast recovery (<150 nsec), 1.4 Amp rectifier. Did your sub meet this spec? An ECG/NTE 571 rectifier ought to sub for these, or perhaps an HER207. The 1024NI2's notable failure is, that increases in value of R325 or R335, in the power supply, cause supply overvoltages that damage ZD202, R241, R334, electrolytic caps in the center of the board, and the vertical IC & its assoc. caps.

QUESTION NO. P720-3: IBM G41 monitor with two transistors that I need a cross ref for; ssh5n90 and Dn or ON-4873.

SSH5N90 is a Samsung FET, TO3P case, 900 Volts, 5 Amp, 150 Watt. A possible cross would be 2SK1358, or maybe 2SK872, available from MCM (800-543-4330), B&D Enterprises (800-458-6053), etc. ON4873 is a Philips HOT, and LJ Enterprises (800-627-8755) has carried this OEM HOT. It is never a great idea to try to sub a HOT, and that's also true here, but if you get stuck, try a Philips BU2520.

QUESTION NO. P78-1: Need cross ref for the following components from a HP D2830A monitor (FCC ID# A3LCGC560); Q503 (C5386) and Q407 (C5002).

Usually, these would both be Japanese "2SC" type transistors. But that FCC number indicates that this chassis is a Samsung (Korean) chassis, and that complicates matters. Toshiba (Japanese) makes a 2SC5386 horizontal deflection transistor (1500Vcbo, 8 Amp, 50W), but, in a confusing coincidence, Samsung itself also makes KSC5386 (1500 Vcbo, 7 Amp, 50W). The two devices are not interchangeable, because the Samsung device has a damper diode, the Toshiba does not. So it is important to determine the transistor's manufacturer, for example, from the logo on the device. A possible sub for the Toshiba 2SC5386 might be Sanyo's 2SC5297, while Samsung's KSC5386 might be subbed by Sanyo's 2SC4123. The "C5002" most likely is Sanken's 2SC5002, rated at 1500 Vcbo, 7 Amp, 80 Watt, esp. if it has an "SK" logo. B&D Enterprises (800-458-6053) lists this Sanken, and both the Sanyo, transistors.

QUESTION NO. P716-8: IBM 6543-301 monitor. When turned on, it turns the high voltage on and there was a picture in about 5 seconds but, after turning it on and off 20 times at does not even start the high voltage any more.

First check/replace C162 & C164 in the power supply. These capacitors can cause problems when marginal, and eventually can kill other parts, so also check resistors R424, R507, R520, R521, R523; transistors Q520, Q521, Q522, and Q600; and diode CR502. If none of these parts are faulty, the bad news is that the CPU IC, Z200 = ST6370J, also commonly marked "IBM PLUTO", is a common and expensive failure item for shutdowns in this chassis.

QUESTION NO. P716-2: IBM-2124 (FCC JVP7154E) monitor also known as Acerview 7154. Need replacement for L304 2mH measured at 768uH and a source.

Try a Mitsubishi, or an Acer (FCC#JVP) supplier, part number 19.40133.001 is L304. In the US, Gastron Technology (626-813-1503), ICM (800-445-1503), and Marcus & Assoc. (800-445-1503), among others, have carried Acer parts.

QUESTION NO. P715-10: Goldstar 1727 monitor, CA-27 chassis. Need the value of R448 that has burnt.

R448 = 390 ohm. Resolder the connections on Q405, that's probably why it burned.

QUESTION NO. P72-7: Philips C2082DAS/II monitor whose line transistor THD4oo, serigraphied V815, on the main board, is in short circuit. I cannot find its characteristics or an equivalent. I have checked the flyback capacitors, they look good.

ST Microelectronics has obsoleted the THD400. If this is the Philips unit made by Fimi (FCC# begins with GZM), it has been suggested to modify the chassis to accept a 2SC3998 for V815 replacement. In addition to the installing the 2SC3998, which will need a retainer clip, and mica insulator with heatsink grease, the modification also requires removing V841, C883, and C884, and installing a jumper wire in place of C884. Be advised that if the THD400 shorted along with other faulty components, the replacement may also blow, if those are not also fixed. Check out R807, all the HV rectifiers = all "BYV" types, & BY584 (this one has a Vforward > 6 Volts!), all the HV Polypropylene snubber caps, microfuses, and coils L807, L802, L803 (T803, & R910, if present). Other common failures are the focus assembly module (gives focus/brightness fluctuations), or the flyback itself (HV-Failure).

QUESTION NO. P628-6: Two Sony CPD-100GST monitors. When computer is on and signal cable connect to it, power green LED comes on, high voltage on, but screen is black. I see RGB on input pins of preamplifier CXA2055P but not see on output. I replaced CXA2055P but nothing change. Could it be the Microprocessor chip bad?

CXA2055P is an I2C Bus-controlled RGB preamp IC. So, this IC may have been put into a shutdown mode by the microprocessor deliberately, for an unrelated fault, or some component along the I2C bus line may be faulty. First, check the obvious. Is the CXA2055P getting both its 5 Volt (pin#7) and 12 Volt (pin#20) supplies? Is there any blanking input coming in on pin#16 (>1.5V)? Is there a good clock signal for the I2C logic coming in on pin#2? Is there I2C data being received on pin#1? Commands, received via the I2C bus, control all parameters of this IC's output. If the IC is being shut down by commands off the I2C bus, download the datasheet to get the I2C command codes, from http//www.sony.co.jp/~semicon/Datasheet/en/a6801860.pdf.

QUESTION NO. P79-9: Two Gateway Crystalscan 1024NI Model #PMV1448. Both of them seem to have a problem with the vertical display. On one of the monitors, the vertical display is about half an inch wide while the other has about a four-inch vertical display. The horizontal display seems to work fine on both of them. On the monitor with the smallest vertical display, I replaced the vertical circuit transistor but that did not change anything.

Check IC201 = TDA1675A for shorts. Be sure the supply on pin#14 is at least 21 V; if not, check components on this line. Check height adjust (pin#7), and components off pins #1 and #12. If not already done, do this modification change jumper J118 to a 1K resistor. Change C201 from 47 uF to 220 uF/35V. Remove any conductive goop around the tiny ceramic caps, like C204 = 0.1 uF/50V, in front of IC201.

Try removing the "peanut butter" like glue from the vertical circuit. This has worked for me in the past.

QUESTION NO. P79-2: Tatung TM6714 17" monitor, picture vertically discomposed. Change caps in power circ.,but no resp.

Check capacitors around vertical TDA 1675,esp.C305,306.

QUESTION NO. P78-10: Gateway cs1572fs monitor, squeals and has wavy horizontal lines through rastor. This question was asked before and two different answers were given. It is not the B+ voltage or R329 which do not match those that are the main circiut board.

The problem resistor in the Gateway 1572FS chassis with the FCC# IAWLX1564 is resistor R331, which is 91K ohms; if it gets above 95K ohms, it can cause squealing and waviness. Use a precision, 1-2W replacement type. Also check R335 & R336, 180 ohms, and R503. Sometimes, VR303 needs re-adjusting, to get ~180V at R331, to remove all the lines from the video. Zener ZD302 (12.2V to 13V) can be a problem when R331 is not the fix. Also check C116 = 10 uF/50V & L106. The Gateway 1572FS chassis with the FCC# IAWLX1572 should be checked for conductive glue problems.

QUESTION NO. P78-9: Older CTX 17" CPS-1760LR monitor. After fixing some bad solder connections on the power supply, I got it to work but the sides are curved in like question marks, and I cannot adjust the horizontal size.

Depending on the exact board version, some parts will vary a bit. Check C135 = 47uF/250V (sometimes unmarked), nearby to C139 and the HD-15 data input plug. Check D410 (ultrafast type, UF5404), pin amp Q305 = 2SD386A, C308 = 4.7 uF/250V; R353 = 10 or 22 ohm/2 Watt; R304 = 33K; R316 = 1K. Check solder on sub-boards and the connections to the main board.

QUESTION NO. P68-3: Lite-On KM411 monitor, blue color is missing. I check RGB unit but I did not find the problem.

Scope the color signals along their way from the VGAplug to the board on the neck of the pcb. If there is no scope available take advantage of the fact that the circuitry processing the three different colors is the same for R,G and B. So try and interchange the signals (missing and present) at strategic points like cathodes of CRT - RGB from chassis to neck pcb - output of color processor - input of color processor - right at the VGA plug.

The problem is TLS1233N.

QUESTION NO. P77-2: IBM 2124 monitor. The horizontal output Xister was S/C. Replaced ok. When fired up a small disc ceramic cap off the Collector of the H/output Xister was s/c. This caused a resistor connected to the cap to burn open. I measured the B+ at voltage a the H/out collector and only had 50 DC. Also no base drive to the H/output. What is the value and working voltage of the disc ceramic cap? What is the vaule of the 1/8 watt resistor connected to the cap? What should the B+ voltage be at the Collector of the H/output? Where is this voltage fed from?+?

If the FCC# on this IBM is JVP7154E, then the ceramic cap is C335 = 220pF/2KV, the resistor R214 = 15K ohm. In VGA mode, expect the B+ at the HOT collector to be around 78 VDC, with 1200 Volts peak-to-peak. The FET for B+ regulation is mounted on the same heatsink as the HOT, but check out both Q316 and Q317, also coils L304 and L305 and assoc. components.

QUESTION NO. P77-9: Acer 7176ie monitor. Replaced c3950, c3951, c3952 for intermittent video problem. Now unit has no horizontal size or pincushion adjustments. All other functions work ok.

First check ultrafast rectifier D308 = FES8JT (600 V, 8 Amp, Trr < 35 nanosec); if it is leaky, it is $4.34 from B & D Enterprises (800-458-6053). Always replace ceramic cap C320 = 100 pF/ 2KV. If D308 is not the problem, check out transistors Q310, Q312, Q313, Q314; diode D307; caps C609, C610, C623; coils L306, L307; IC301.

QUESTION NO. P72-1: I need a source for replacement back lit lamps for Toshiba notebooks. They are very tiny, about 2-4 mm in diameter.

If you insist on a new exact-replacement lamp assembly, dressed out to fit your model notebook, the source is probably going to be Toshiba. Toshiba sells the lamps for $150+ apiece, given the proper part number, which depends on whether the LCD display ass'y. is truly made by Toshiba (like p/n# P000197200), or is a Sharp display (like p/n# P000194950). If a Toshiba service center actually does the repair, they will probably want to replace the entire LCD display, for an astronomical price. If you can accept a close match on the lamp (and sometimes maybe having to drill a mite with a Dremel tool), JKL Components Corp. (Pomona, Calif., 800-421-7244) is a domestic producer of these CCFL lamps. Pick the closest matching tube from their website at www.jkllamps.com/fluorescent.html Their bulbs and accessories are $10 - $15 from a distributor like Digikey. If the bulb is damaged, or failing, you will need a new one. If the bulb does not light, but isn't damaged, it may also be a bad inverter, or a cheap fix like an open fuse (incl. any SMD fuses on the inverter board), or an open thermal fuse or electrical connection. These inverters are HV & high frequency, so watch out for RF burns, and keep any leads short. For more information, see the JKL home page at www.jkllamps.com , or the answer to question P622-1 on the Monitor Repair page.

QUESTION NO. P69-1: Acer 7176IE monitor, will not power up, and there are no lights lit. I have 83vdc to the fet.

To answer my own question, I found Q601, shorted ebc, then IC601 had only 3.5v on pin 7. replaced q601, ic601, and, had 11.5 volts on pin 7. Replaced c605=22x50v, this allow the monitor to power up. At this time there is 17.5volts on pin 7 of ic601, and, all is well. Replaced c607=100x50v while you are there.

To add to my answer there was 167v on the drain of fet. This monitor came back in three weeks with the same problem of no startup. I found that d603 [1n4001], causes a low voltage condition at pin 7 of ic601. All other componets checks out to be ok.

QUESTION NO. P628-1: I need a description of q5e4 in mainboard of nec multisync xe15 monitor.

Q5E4 = 2SD1763. An NTE2576 would be a close substitute for that type.

QUESTION NO. P628-8: AOC CMLB-736 monitor was dead. After changing Q804 2SC3996 and Q805 which were short cicuit, the set worked for short time with reduced width and Q804 running very hot. The HT voltage seems to be correct and I have checked the capacitors around the HOT.

Replace C821 (between T801-HO-Driver and Base/HOT) 4,7湩/35V.

QUESTION NO. P628-3: Apple multi-scan 20-inch video monitor, model M1823, powers up briefly, then shuts off, with yellow light blinking. High voltage comes up, at about 25 kV, apparently normal. Vertical sweep OK (vertical bright line) but no horizontal sweep during the brief period before total shut down. Pulses to base of horizontal drive transistor are present, but about 100 kHz, even though h-sync from computer is only about 25 kHz. Problem? Collector of horizontal (yoke) drive transistor floats up to about 70 VDC, then, when sync pulses start coming in to the base, suddenly drops to 0 VDC. Part of shutdown, or cause of shutdown?

First, if you are using a Sencore, be sure to use the special adaptor for this Apple unit. Check for open Sony microfuses, PS500, PS501, PS800, etc. Check P-FET Q511, and also the diode installed between its source and gate. A bad Q511 may be leaky, shorted, or it may simply not turn on properly, so besides ohms-testing, see if its drain responds when the unit is sending pulses to the gate. Check R851, R868, and C822. Also, do a general check of caps in the power supply; usually some are bad for ESR or value. Other common problem components are D824, D825, IC404 = TL082, IC801 = 4049B, flyback.

QUESTION NO. P628-4: Mags DX 17F monitor, Q109 was shorted. Replaced transistor unit worked Ok. When turned on from cold no horisontal drive to base of Q109.

When Q109 blows in this model, several other parts MUST be checked or replaced, because any parts that died can then kill other parts, as well as any replacement parts. You should also check or replace caps C120, C123, C147 (at the very least); coil L105; resistors R177, R181, R939; fast-recovery diode D116; and FETs Q107 & Q116. If coil L105 looks even slightly cooked, get a new one from Mag. Caps C120 and C123 should probably just be replaced regardless, and also R181 if its value has changed. Replace Zener ZD107 (6.2V) if it is below 6 Volts. HV is nominally 27 KV (HV adjust is VR105), and the HV shutdown is set for 29.5 KV (trip adjust is VR106). Occasionally, the flyback transformer is bad.

QUESTION NO. P622-1: Where can I buy replacement fluorescent bulbs for a Toshiba 315CDS laptop? I believe it is a Dual scan passive matrix. The bulbs is displaying very bright areas across the bulb and as a result the picture has bright streaks. I temporarily put black tap over the areas that are the brightest and that did the trick. I would like to still replace the bulb though. It does not have any kind of number stamped on it. The bulb is about 10 inches long and about 1/16 of an inch in diameter with wires mounted already on the ends with rubber boots.

If a lamp with a 3 mm diameter will fit the unit, Digikey (www.digikey.com) carries CCFL lamps from JKL, at about $11 apiece. You need the lamp's exact dimensions in mm. to choose the correct size. An exact sub (but used) might be obtained from www.buylcds.com Those would cost about $55 apiece, but a new CCFL lamp from Toshiba would probably be several times that price. Also, any lamp that's not physically damaged, should have its inverter checked out as well (JKL's inverters are also at Digikey, $15, plus optional connectors, $2-$3).

QUESTION NO. P68-2: IBM 6542-103 (G40) 14" Monitor is unbearably fuzzy. External controls (contrast & brightness) have only slight effects. Have been unable to find schematics. Have found Vertical/Horizontal hold. Hoping to find focus.

Focus control is located on the side of the flyback. However, if the focus adjust also raises and lowers the raster you have a bad flyback and it will need to be replaced.

QUESTION NO. P622-3: 10 IBM G41 6542-301 Monitors, all have problems. Where can I find service information on these?

Try M. I. Technologies, www.mitechnologies.com (document 2884-L).

QUESTION NO. P67-3: Where can I find the amplifier/buffer for RGB tht is an Hitachi made FA4111 for a Sony monitor?

B & D Enterprises (800-458-6053, www.bdent.com) is listing Hitachi's FA4111 for $23.46.

QUESTION NO. P617-8: Gateway 2000 1024ni monitor with very poor horizontal sync. I have confirmed 12 volts dc getting to the horiz. osc. ic. Static tests on components have so far been unrevealing.

If your 1024NI is the 1024NI chassis made by KDS (FCC# EVO), and the symptom is horizontal jumpiness and unstable image, check/replace the control pots on the front panel, esp. those for Horizontal Size & Phase control. They are of low quality, and are known to cause that symptom.

QUESTION NO. P617-6: Princeton EO40 monitor does not have vertical deflection. The IC tda8351 was replaced, no change.

Troubleshoot it using the voltages on the TDA8351 (pin#5 is ground). Is it getting any Vp (9V-25V range) on pin#3, or Vfb (up to 60V) on pin#6, the output supply? Is the differential input signal coming in on pins#1 (+ input current) & #2 (- input current)? Or is the Guard circuit activated, and showing 4.5-5V on pin#8? A high voltage on pin#8 shows the IC is deactivated, for one of these reasons; an open circuit (bad connection or open component), or a short circuit between the output pins #4 & #7 (like a shorted vertical deflection coil), or from one output to ground, or (less relevant) from a thermal overload or during flyback. Does the sense resistor between pins #4, and #9 (the feedback input), show a sawtooth voltage waveform?

QUESTION NO. P614-10: AOC CM335 monitor is dead and the internal fuse is okay. There are no obvious burnt components or dry joints on the boards. The power on lamp is not lit and the switch checks out okay. The thermistor is warm to touch when on for a while. Are there any typical problems that I may check before I suspect the LOPT.

The usual cause of the AOC CM335 PSU not starting is a high or o/c R907/R908. If the HOT is shorted replace C512. Also replace C512 if the HOT runs too warm.

QUESTION NO. P615-9: Proview PV 564D 15" monitor. You can barely see the screen with the contrast and brightness adjusted to their max. The images on the screen do not appear distorted just very hard to see.

Bad CRT's are very common on these, esp. if it is a Samsung CRT. If the heaters have a solid 6.3 V, and G1 & G2 aren't too low, then 100 to 1 that it is dim from a bad CRT. Replace it, there's no point in trying to restore bad Samsung CRT's.

QUESTION NO. P614-5: Mag DX17 monitor, has no high voltageand shorted hot. Taking advice on this page of tips I replaced several parts including c123,c120,q109,L105,r177,d116,q116,c908, r181 checked good. The tech tip also makes reference to q103 2sd1887. I have searched and searched to find it on the main pcb to no avail. Is there such a part and were is it hidden?

This is an error, for 2SD1887 is a HOT, and the HOT is Q109 in the Mag DX17F.

QUESTION NO. P518-7: Philips 14A monitor, connected with computer. noe. The led can turn from yellow to green, but no HV. Second power FEt5P25. There have about DC 180v voltage in "S","G' ,but no voltage in "D".

Although number for the FET is not complete, it is possible to tell that this FET is a P-channel type. With the same 180V voltage at both the gate (G) and the source (S), this P-FET will not turn on. So trace back from the gate input, and find out why the gate drive circuitry is not functioning.

QUESTION NO. P68-9: Packard Bell 2020 (FCC ID DK42020; GVC Corp.) monitor, 10 electrolytics are removed from the main board and I need their values: C316, C321, C322, C402, C406, C407, C411, C416, C417 and C439.

C316=100/16;C321=47/16;C322=10/16;C402=4,7/50;C406=10/25;C407=10/50;C411=100/16;C416=47/16;C417=47/16;C439=3,3/50V.

QUESTION NO. P68-10: CTX 1451 Monitor came in with power supply overload (click-click) problem. Replaced bad HOT. Now image has horiz foldover, raster pulled in one-two inches on each side. All controls work except horiz size - provides minor variation but has equal/opposite effect on vertical size.

There are several different chassis for CTX1451 (different FCC #'s), so these locations cannot be guaranteed, but if C722 = 47uF/50V, test/replace it; also, R434, D104, Q406, Q407, and Q410 should be checked.

QUESTION NO. P67-2: Aoc 17" mod鋩e 7Hlr avec q420(bu2525ax) en court circuit et r113=1ohm/1w coup� mais tout grille de nouveau apr廥 quelques minutes de fonctionnement.

I believe this chassis is the same as the Royal 1782 model (FCC# HSU). The usual problem is the horizontal driver transformer has a defect, and overheats Q420. If you cannot rewind the transformer, or find a replacement, one trick is to solder a second capacitor = 10 uF/63V in PARALLEL with C476 (near center of board, below Q411). This should cause Q420 to run cooler if the transformer was the problem. Also check R498 = 1 ohm/2 Watt, Q414, T403, FET Q103 and the black cylindrical coil close to this FET, and the diode in series with R113.

QUESTION NO. P64-1: Two 15" Voxon monitors that need the Horizontal Output Transistor marked 2520DF.No cross reference found. I 'd also like to know where I can get a service manual. Another 3 monitors of the same kind only display the upper half of the screen(lower half is black).

That will be a Philips BU2520DF, a transistor with an integral damper diode; there are many possible sources, among them MCM (800)543-4330 and B & D Enterprises (800-458-6053). Also test the flyback after replacing the HOT. Without having any model numbers or FCC numbers, there is no way to get specific about your symptoms, or sources for manuals. If the FCC number is present, look up the manufacturer from the FCC number, and try them for manuals. For the units with vertical collapse, if these only have shrunken video, but are syncing the video properly, try testing the vertical IC with heat or freeze, or swapping it out. If, however, the remaining video in the top half is not syncing correctly (rolling, lines in the video, etc) and if those units also have a TDA9103 or STV7778 IC, those IC's can cause that kind of symptom when bad.

With respect to the voxon monitors with the vertical problems, I just repaired one with same symptoms by replacing the C3205 transistor near the vertical output IC using a NTE-11. Replace it even if it checks good because it breaks down under a load.

QUESTION NO. P524-6: HP-A4033 (GDM-20E01) monitor. See answered question P510-5. I replaced Q511, IC404 and checked all the caps per answer. Turned the unit on and everything was fine for a few days. Upon power up on day 3 the Win98 Splash screen was fine from the center of the screen (top to Bottom) to the lefthand side. From the center to the righthand side it was way out of focus (top to Bottom). As it warmed up I could see the focus getting better and then just as it was almost all in focus, the picture died and I heard the screach again. I took it apart and found Q511 and Q512 to be ok. R470 was burnt (but not open) again. Is 1K the right value for this resistor? I cannot find any bad or leaky components.

Probably a bad flyback, foucu pack, and/or crt.

QUESTION NO. P526-10: IBM 6543-301 monitor (G50) with no high voltage in the hot. There is 45vdc and 45vdc in the neck board. When I start the monitor the led blanking "green orange". I changed the IC number tda4855 and tda4866 with no change. Also, what is the pin out for IC ST6370J5B1/BLI.

Is there B+ at the collector of the h output or B+ terminal of the flyback? Is there B+ at the collector of the h driver transistor, do you have any HV at initial startup or does the unit totally refuse to produce any eht? What value is the regulated B+ from the smps? It should measure roughly 125 - 130 volts. If there is no source to the deflection ckts then look for probs in the regulator/smps.

QUESTION NO. P64-7: Princeton EO75 monitor, HOT shorted 2SC5270A. Need specs or substitution. It appears that Princeton eventually substituted another part for this transistor because of repeated problems.

2SC5270A is a Matsushita HOT, rated 1600 Vcbo, 12 Amp, 120 Watt max. Tfall is typically 0.12 usec; Tstg is typically1.5 usec; gain is 5-12 (8 typ) at 6 Amp Ic; Vce[sat] is 3 V max. (1 V typ) at 6 Amp Ic/1.5 Amp Ib. It has a TO3PE case, for which that max. wattage rating is very high. This, with the 1600V Vcbo rating, make this one difficult to sub exactly. But, MCM (800) 543-4330 does list 2SC5270A itself for about $9, and B&D Enterprises (800) 458-6053 for about $13.

QUESTION NO. P526-5: Nec JC1741UMA monitor, the power light is on and the tube sounds like it is charging but there is no picture on screen.

If there is power and high voltage, but no video, one cause is forgetting to put the Sync switch on the back panel to its "on" position! Also, check that the BNC/D-sub selector switch on the front panel is set correctly.

QUESTION NO. P526-4: Several Compaq model 471P FCC ID CSYSC-428VSA have vertical def problems. The problem is the IC201 and the heat sink compound was dry (TDA8351). The IC seems to be heating up. All caps in section are good. I checked it and it is about 145 degrees. Is that normal?

This Samsung chassis is notorious for burning up vertical IC's. There should be a resistor (R201?) off pin 6 that may also be damaged, the exact resistor value will vary depending on chassis version and CRT yoke installed. Any caps off of pin 6 should also be checked. You may need to adjust the B+ voltage to pin 6, or play with that resistor's value, to get the IC to run cool now with the other (aging) components; too low a value for that current-limiting resistor, or conversely too high a B+ voltage to pin 6, can cause the IC to overheat. You should not be exceeding 36 Volts to pin 6 of TDA8351, if adjusting the voltage. Try starting with a resistor 50% higher in value than the current value, if you're trying a different resistor.

QUESTION NO. P430-6: Mag Innovision 17f monitor, has a jitter that occurs once in a while slightly and close to the middle of the screen there is a line going from top to bottom. I replaced everything in the kit except D116, Q116 ,Q103,and C908. Each of them tested good. I am going to replace C908 anyways.

Usually a bright vertical line toward the center of the screen is in indication of a shorted winding in the yoke. Occasionally a winding in the Flyback can produce a similar result. The bright line accompanies or is a precursor to a folded image in that area.

The Mag DX17F has a line in the center of the is commonly caused by the wrong h.o.t or a H.O.T going bad. I have seen 2sc4747, 2sc5048, 2sd1887 transistors listed. I tried interchanging these and in every case when the one that came originally in the monitor was changed to one of the others it caused a faint verticle line located in the center of the screen. The line location changes with resolution and becomes two lines at 1024x768 and higher.

QUESTION NO. P430-4: Nec 5D monitor with no power LED, no heater in picture tube, but has hi-voltage present on front of screen. Power supply checks out, 170v, 85v, and 24v are present.

The NEC 5D gets its filament voltage (6V) from the Video input board, that is the board nearest the back. If you trace the twin ribbon cable from the CRT board to this board you will see where it is fed from. The six volts is fed through a resistor which ultimately derives it's supply from a 12 volt source. I think you will find a 12 volt regulator on this board that is supplied from the 24 volt source coming into the board. This is a common problem. Also check all components from the 12 volt regulator to the 6 volt feed. A schematic REALLY helps, since this board has circuit traces on both sides. The power LED also will not light when this circuit does not work.

QUESTION NO. P524-2: AOC 4Nlr monitor. It works fine in DOS and Windows at 640x400, but at 800x600 the picture rolls.

Check out IC201, the Weltrend WT8042 chip, as well as its crystal/resonator, and any associated capacitors. LJ Enterprises, MCM, and others carry these IC's.

QUESTION NO. P518-9: Acer 7156 monitor. I replaced the flyback and got the monitor back to life. But now the picture is about an inch too wide and the front panel horizontal control does not have any effect, nor does the pot inside the monitor. The rest of the digital controls work perfectly but when pressed the one corresponding to the horizontal width all the green LEDs flash weakly while pressing the button.

This symptom is usually caused by a shorted diode in the horizontal output circuit. Thoroughly check all diodes, especially the larger ones around the flyback area. Occasionally the Horiz. Output Transistor will short B to E. If the output uses a transistor with an internal damper diode, it will show shorted anyway (to a meter). However, if the output does not have an internal damping diode, then it should not show shorted B - E. The Horiz. and High voltage will often still operate even though the output transistor is leaky or shorted.

QUESTION NO. P514-6: Highscreen MS1457 LE-II monitor. After 15min picture gets darker and out of focus, no significant change in picture geometry. Vendor's diagnosis was 'CRT bad', now customer wants second opinion. I would think of screen divider/flyback/eht being at fault. Monitor was operated at ~48khz h-scanrate. Overheated/cracked flyback?

Check the HV and focus potentials, make sure the focus voltage does not change when adjusting the G2 bias. Check the voltages with and without the crt connected. That is with the anode and crt socket attached and removed from the crt. Make sure the regulated B+ is correct to the deflection ckts also.

QUESTION NO. P511-2: Mag DX17 Monitor suddenly lost focus and got slightly brighter (no noise or burnt components). Turning down HV and adjusting focus and screen restored focus, but picture is now darker and smaller.

This could be either a defect in the screen/focus voltage divider section of the flyback, or some conduction may have developed between the focus and G2 grids within the CRT. If the focus and screen controls were interacting, and affecting each other's function while being adjusted, this would favor leakage between the CRT grids. In that case, see Anatek's Tips & Tricks webpage, for a trick on how to "zap" the CRT pins and clear these kinds of CRT shorts. Or, if the flyback has developed a leakage of high voltage into the screen/focus divider, replace it.

QUESTION NO. P520-5: Several Orchestra Trumpet (KDS) monitors all with the same problem. Horizontal size adjustment has no effect. The display is pincushioned and too wide. The adjustment pot and wiring seems O.K but it has no effect on the display. Where can I get more online information on pincushion circuitry?

One commonly-used circuit for controlling both horizontal width and pincushion (also called "East/West" or "E/W correction") is described in Sam Goldwasser's article On-Line at http//plop.phys.cwru.edu/repairfaq/REPAIR/F_deflfaq.html. Failures in this type of circuit can give a too-wide and pincushioned display.

QUESTION NO. P427-2: Ultra VG-1520 monitor FCC IDk17vg-1520, dim and fuzzy picture. I have exchanged the lm1203n and checked all the caps, resistors, transistor on the crt print with no luck. When I first opened the cabinet, I could see that the shielding on the crt print did not have any connection to ground.

Check the tube to make sure it is in good shape. Try to adjust the focus on the flyback. If the focus is at the end of the pot than it sounds like you have tube problems. Restore the tube for extended life.

QUESTION NO. P520-3: Mag DX700T monitor which is repeatedly blowing the HOT and R173. The board has been thorougly checked for dry joints. The fault occurs when the image size is increased to fill the screen. On resizing, the OSD loses sync and the picture folds back over itself on the left side before emitting a hissing sound and blowing the HOT. I have the schematic and some voltages are lower than expected. HOT collector pulses are 800v p-p instead of 1.2KV. The waveform is otherwise clean. I noticed that the HOT is running at a higher temperature than normal. I suspect either L103, T102 or the horizontal deflection yoke. Is there any means to find out if any of these is faulty? Are there any internet suppliers for the coils?

Mag Technology (or Mag Innovision) is the primary source of coils, etc, for these units. The worldwide website is at www.magtechnology.com in North America, you can also try website www.maginnovision.com. For the DX700T, also check out Mag coil# LM*-751-401*0 LSE ; this coil may go bad when Q106 and R173 get blown. Also, capacitor C548 is a common problem. You may wish to check with Mag Tech Support about C548, some units have had an upgrade of this cap with a 0.1 uF/500V ceramic cap (original cap is 1 uF). In the US, Mag Tech support is at 714-751-2008, x895 ($25/10 min), and Mag parts can be had from Mag Innovision at (800)827-3998.

QUESTION NO. P520-8: Pacom mod CL15E monitor, picture is too wide. The panel controls have no effect towards correcting the problem. I have checked all caps with an esr meter (all ok).

If the FCC# ends in SM585F, check out capacitor C225 = 4.7uF/50V once more; ESR meters will not find shorted caps, or changes in capacitance value.

QUESTION NO. P514-4: Mag DX15Fe monitor in which the CRT was replaced. Purity adjustment is OK but when converging the red and blue the red does not seem to be as high in the vertical sweep. If you converge at the center the red is down from the top and up from the bottom.

Answering my own question, I tried another CRT in case it was bad with no improvement. Changing the yoke solved the problem. It does test OK but marginally. I still do not know why it affected only the red gun though.

QUESTION NO. P518-1: Gateway 15" Vivitron monitor made by Sony and is equivalent to their 15" Vivitron. The color is not right in the lower right hand corner. The monitor worked for a while like this, but now it will not power up. Both LED's flash now.

First, there are two Gateways that are 15" Sony chassis, which differ from each other. The unit is in shutdown (blinking LED's); the potential causes will depend on which exact chassis it is (indicated by the FCC# or Sony chassis#). But here is one point. The color problem sounds like a warp in the aperture grill in the CRT, requiring a new CRT, though it probably isn't the direct cause of the shutdown. But it may indicate the unit was roughly handled by the owner, and the Sony 15SF1 version (Sony SCC-H01A or SCC-H35A chassis types) can get cracks in the PC board traces, or broken pins on IC's, esp. near the center of the board, if rough handling causes the CRT to whack on the big heatsink there. Those cracks/broken pins are one of several causes of shutdowns in the 15SF1. There are also Gateways that are Sony 15SF2 chassis, which differ from the 15SF1.

QUESTION NO. P518-6: I need to identify a shorted diode D103 (1DQ065C) in a Mag Technology DX17F monitor (Manufactured July 1995). I cannot cross reference it.

IRF's 11DQ06 is a 1.1 Amp, 60 Volt Schottky rectifier ('5C' is a mfgr.'s code). Be aware that a 1 Amp Schottky only gives roughly 0.3V in the forward direction with a 1 mA test current, and so can seem shorted in some tests. If a replacement is still needed, Digikey (800-344-4539) lists it, as cat.# 11DQ06-ND, for $0.42 each.

QUESTION NO. P415-8: NEC XP17 monitor that powers up but immediately loses HV (I can see a picture very shortly and Green LED is OK). All transistors around the FBT seems OK. Also vertical Def seems OK.

I figured the problem out my self. It was the FBT that was defective.

QUESTION NO. P514-9: Two Mtek 17" monitors with same IC, a LH2426 with inputs damaged, giving a blurry image. The LH2426 is a video amplifier made by National. As an obsolete device, where can I get a substitute or a circuit to replace it?

B&D Enterprises (800-458-6053) lists LH2426S for $42 each.

QUESTION NO. P512-9: I need a flyback for a Hitachi monitor. The part number on the flyback is KSF-61478. I need a supplier for these parts.

Try ASTI Magnetics 1-800-221-1828.

QUESTION NO. P513-5: Sony GDM-17e10 monitor that powers up and then goes into shutdown. The "power" and "power saving" LED's blink and the "cent" LED is on solid.

Check FET Q511, HOT Q512; fuses PS500 & PS501; check all the electrolytic capacitors in the power supply section for leakiness or bad ESR.

QUESTION NO. P513-3: Compaq 461 monitor, fccid BR8SM-5514N (made by ADI Corp). It comes on and works but has terrible linearity problems. I found no controls (pots) on board for lin adjustments. I did find an ext plug that goes to the memory daughter board. Does this unit require an external module for programing? What goes here?

ADI chassis with that FCC# uses an ADI software/interface package for geometry alignments. ADI was selling that package for around $500 awhile back.

QUESTION NO. P510-4: Sony MultiscanHG 17 inch monitor CPD1604S that displays its image as trapezoid a shape. Any adjustment I make only lasts until power off and shifts the narrow part from top to bottom.

Go to the DA board, Sony# A-1346-069-A. If you can find one at a Sony distributor (they are discontinued), you might just replace the board. Otherwise, check all the SMD caps for leaking or high ESR, chances are there are several bad ones that need replacing. Esp. check C328 and C334, also IC303 = TEA2031A. Clean the board well of any leaked electrolyte, repair any damaged PC traces, and run wires through any damaged through-hole connectors underneath these caps. Readjust RV309.

QUESTION NO. P510-5: GDM-20SE1 Monitor was dead. Q511 and Q512 were shoted. R470 was burnt. I replaced both Q's and R470 with a 1K (I think this was the right value). I also found ps501 open and replaced it. Everything else checked ok. Powered up at 640 X 480 and ran for a few minutes. I changed to a higher res and heard a screech and lost power. It took out ps501 again and found Q511 shorted again. On the PCB D504(Zener) is missing??, and C511 is a diode instead. (which seems to check good.) I also found R638 in the PS to be burnt a little, but not open. ( looks like .o47ohms) Q512 still looks ok. What is the value of diode in the C511 positsion? Also the replacement Q511 was a TO-220ab so I had to use a mica insulator.

The diodes off the gate of the FET Q511 are for gate protection. When a zener is used at location D504, generally 13V, this protects against gate overvoltage. Some chassis, like yours, have a different diode, protecting against gate voltage reversal, and is either a germanium diode (like 1N132), or a Schottky type, which is chosen for its low forward voltage. R638 = 0.47 ohm/0.5W/ fusible. With this model, check all the electrolytic caps in the power supply for leakiness or bad ESR; if bad, they can overwork and blow that circuit. Also, Sony had a bulletin recommending that the spark gap be replaced with a 300 Volt unit. Perhaps also see if D824, D825 are leaky under load.

QUESTION NO. P512-3: Hewlett Packard D2807A 17" Ergo Ultra VGA Monitor. Kicks on for split second. High voltage starts, then seems to go into shutdown or power save mode. Most parts seen to be fine. HP NOT helpful at all.

Does the FCC# start with ACJ? If so, this "HP" is actually a Matsushita (Panasonic). Their units are known for cracked PC traces, due to poor board design, so start looking for these. A common site is near where screws fasten down the board, but look the board over top to bottom.

QUESTION NO. P511-8: Dell p1728u monitor. The monitor powers up but there is no display. The contrast and brightness leds are flashing on and off. I have changed ic 902 already. Also the neck is lit up which appears that there is high voltage.

I think you will find that this "Dell" monitor is actually a Mitsubishi chassis. This Mitsubishi's video cable does not use the standard VGA pinout, and using a standard VGA cable will not give any video. Get the customer to bring in their video cable for this monitor. If you have to make your own, the pins going into the monitor are pin#2 = red; #3= Red ground; #4 = green; #5 = green ground; #6 = blue ground; #8 = vert. sync.; #9 = horiz. sync.; #10 = blue; pins# 1,7, and 11-15 are no connection.

QUESTION NO. P49-5: Acer 7176I 17" monitor with Q311 (2SC4542) shorted. R338 burned open and R379 badly charred as well as R344 which tried to reflow solder itself. I need the values of these resistors. Land pattern around R338 also badly charred and damaged but looks repairable. I would guess that Q311 caused all the damage.

The values for R338=10 Ohm;0,5Wt R379=18K;0,25Wt R344=82 Ohm;3Wt. Most of them connected to +12V circuit.

QUESTION NO. P56-8: Dell ultra scan 17tx monitor, shuts down after about 2 seconds,and the amber LED flashes. No horizontal startup. I checked the H trans. and related components, all check O.K. The 5-volt stand-by voltage remains after shut-down,but all other voltages come up about half-way then shut-down. Checked continuity on video cable, also checked Q417,420.

This "Dell" is probably has a Sony FCC#. If so, a common failure part in those is R613 = 390K (if value bad, replace with 0.5W rating, also replace R612 & C600). Check all "PS" type fuses (PS401, PS402, etc, around 8 total) and R638 for open; check IC401 = LM339 type, & IC403 = LM324 type; also check diodes D441 through D446. Check if VR401 is set for ~28KV. Sometimes the Eeprom goes bad in this Sony.

QUESTION NO. P56-6: Dell D1726S-HS monitor. I need a hibrid ic location on pcb is HIC 401, on the part you can read this HS17 IEKS. Who is selling these parts?

If you check the FCC#, you will likely find that your "Dell" monitor is actually made by Samsung. If so, try getting this HIC from a Samsung supplier. In the US, for Samsung parts, you can try Herman's Electronics (800-938-4376) or J&J International (800-627-4368) on the east coast; Amcotron (800-344-3882) on the west coast; or maybe Samsung itself (800-726-7864).

QUESTION NO. P46-2: Sun monitor FCC # AK8GDM500PS, the green gun not functioning. I narrowed down the problem to the PCB directly behind the CRT labled "A" (sony part # 1-667-235-14). I have traced the PCB traces back from the CRT to a chip labeled Hitachi FA4111 which is heatsinked directly to the metal chassis surrounding the monitor. I suspect that the problem may lie here. What does this chip do, and am I on the right track?

Yes, replace the IC.

QUESTION NO. P47-9: Old Sony CVM-1225 color monitor. The unit has about a 3-4" band on the left side of the raster that is significantly darker than the right side. The width of the band changes and the edge of the band is a moving ripple. The problem occurs with B&W as well as color signals. The output of the video amps seems to be OK. 24KV is OK. Many other voltages are lower than called out on the schematic.

Start replacing power supply caps. An ESR meter would be helpfull finding the bad one.

QUESTION NO. P428-1: CTX 1565D monitor. Apparently the user had the monitor in use face-down for an hour. The next day, when turning the monitor on, it was dim for 1/2 hour and then went back to normal intensity. After shutting it off for a few hours and turning it back it was dim again and did not return to normal intensity.

Check for a bad cap in the filliment voltage circut. Or maybe bad conections.

Resolder CRT socket to videoboard- the most common problem for 1565D.

QUESTION NO. P414-9: TVM md14IIIs2(lr) monitor. It has shrunk horizontally and it is out of focus.

Check horizontal transformer and check focus voltage it mybe good to check the yoke windings.

QUESTION NO. P414-7: HP A4033A monitor. The high voltage comes up when power is applied, but immediately after the monitor enters power saving mode. The power save light and power light blinks while the CENT light remains solid. No other LED's are on. The component failures suggested in the answer for question P210-1 has been checked and found OK.

This may be a failure in the horiz. deflection circuit, which is a separate circuit from the HV circuit. If you have already checked those parts indicated in P210-1, and also all the "PS" type fuses everywhere, then check the horizontal yoke transistor Q512, and the associated caps, rectifiers, etc. in the deflection circuit, and the FET circuitry regulating B+ and pin correction for the deflection circuit. Also check ALL the electrolytic caps in the power supply, these chassis often turn out to have very many bad/marginal caps; for sure, check C611, C612.

QUESTION NO. P428-3: CTX 2085 monitor with no screen brightness. The control pot does not work at all. Pot is good, contrast works but no brightness. Q401 (BF483) should measure -14v at collector but is measuring -156v. Replaced transistor but still have same problem. As a result G1 supply to negative.

Check for lack of power to convergence output devices, such as open fuses and or fuse resistors. Also check for dry solder connections. As old as this set is you may also want to check any electrolytic capacitors in the convergence and supply circuits.

QUESTION NO. P429-5: CTX1765cd monitor, FCB DBL1765cd. Screen is too dark, otherwise all OK. "Screen" pot on fbt has no effect at all. Any other G2 or RGB adjustments?

The screen pot will not work, because RGB & brightness settings are controlled digitally through an RS232 port. If you do not have the CTX software/hardware setup, a possible workaround is to cut the G2 line from the CRT bd, and insert a high-value (1 Mohm or so) resistor in line with R419 = 3.3 Mohm, to increase the total resistance.

QUESTION NO. P421-5: Optiquest 4000DS 17" monitor, does not have High voltage. Power supply voltages are OK per printing on board. Led lites indicating a vga signal present. The wave trace at base of HOT is not a good sawtooth signal.

You should not expect a sawtooth at the base of a HOT. Drive to B of HOT looks more like a rectangular with negative spikes on falling edge
__ ___ .... hilevel ~+0.7V
!____! !__ .. lolevel ~-2V
! !
! ! <-- 1st neg. spike below -5V
If signal to base of hot is other than rectangular waveform check drive (which is often done by a transformer - check the signal on its primary - it is rectangular again). If drive to hot (as shown above) is present scope C of hot.- ATTENTION ! Make sure your scope can handle >1200volts peak. You should see needle like pulses starting at falling edge of hot-B drive. If no trace there or scope not able to safely display 1200Vpeak, check the DC voltage at the collector print with HOT DISMOUNTED. Maybe the supply voltage (+b) to or through the flyback is missing. If so and you find a burned fuse or fusible resistor in the supply path, check HOT for CE shorted.

QUESTION NO. P331-7: Three Samtron monitors, horz o/p (Q306) last for 2 min then over heats and shorts.When defection yoke is unplugged, Q306 does not over heat. I have all ready swamped the following parts from a good monitor: FBT, defection yoke, all coils, and caps in defection circuit, H.D. xfromer, SPCTxformer. When yoke is plugged back in, right side of screen is not filled and linearity and pincushion is very bad.

Since you did most everything, all that is left would be to check pincusion output transistor/ic and adjacent coil/caps towards deflection. Check damper diodes (if external) from c of HOT to GND. And besides caps and coils recheck diode(s) and low resistance/high wattage resistors in horiz linearity control (in series with yoke). Are you sure the applied horiz. scan rate is not too high since I understand you have the same error on three sets?

QUESTION NO. P427-7: Sony cpt-17sf2. c5023cs integral chip dead. Is there an analogue and what are the characteristics?

UPC5023CS is a customized IC, configurable by its maker (NEC) to the customer's specifications, so there is no alternative. Even another UPC5023 IC from another application might be configured differently inside.

QUESTION NO. P427-9: Radius 0461 monitor Intelli color display 20e. The fault is that the EHT comes up for a second or so and then dies.

This Sony chassis is probably in shutdown, esp. if there are two LED's are blinking to indicate this (another LED may be on solidly, to indicate the type of shutdown). In general, given no specifics, check ALL microfuses (marked "PS"-something) for open, check FET Q511 and HOT Q512; rectifiers D504, D824, D825; IC404 and IC801; resistors R638, R851, R868; capacitor C822. Also check ALL electrolytic capacitors in the power supply. The flyback transformer (LOPT) can also go bad.

QUESTION NO. P427-3: Six Orchestra (KDS) Trumpet Monitors. All have color smearing to the right of very dark or very light colors. Two of these monitors also have pincushion/horizontall adjustment problems.

Replace the six 1 uF caps (three bipolar, three high voltage) on the CRT board, these are a known cause of smearing. The front panel adjustment pots on the units with manual controls (H.size, H.width, H.phase, etc) are low-quality, so replacing these may solve the horizontal adjust problems. Sometimes there is a faulty signal cable (try wiggling it).

QUESTION NO. P414-4: Philip fsr871cv which is the same as Digital PCXAVF4 or Compaq 480/480p/481 monitor. When doing power up diagnostic it first shows " H/V sync off" and then " High voltage failure" then the unit shuts down.

A bad flyback unit generally causes this type of HV shutdown in these models. Sometimes a bad focus assembly block can also, if you see focus or brightness problems occurring on the display before it shuts down.

QUESTION NO. P47-7: Mag DX1795. With power, green LED comes on and then a click with no high voltage. I check the HOT and it is ok. No visible cracks or cold soder joints.

If there is no horizontal drive from TDA9103 IC to the HOT, the TDA9103 may be bad. Also check if there are problems regulating the 12 Volt line from the power supply.

QUESTION NO. P421-7: Premio h566 15" monitor. Works fine until it warms up. At first it just gave the hour glass effect, now it is just a shrunk picture (about one fourth of the screen and rolling fast). Turn off and let it cool down for 15 minutes, and it is good to go for another hour or so. I used cool spray on Vertical and horizontal areas, with no noticeable effect.

Replace the 42-pin PSDIP IC, TDA9103.

QUESTION NO. P420-2: What is a transistor bearing markings FS14SM? It is used in Acer computer monitor 15".

FS14SM is a Mitsubishi FET, rated for 14 Amps, in a TO3P case. For more on Mitsubishi FET marking codes, see answer P226-5 on the VCR Repairs page.

QUESTION NO. P419-8: Six ADI SM-5514a monitors that all display a green led and will not do anything else. I checked the hot and that is ok. Could it be the Microprocessor chip that is on a small daughter board?

The Zilog processor on the standup logic board is a common problem in this chassis for this symptom. Get its complete number and get a replacement from a supplier like LJ Enterprises (800-627-8755) or CCS (800-356-1227). IF the supplier wants to supply a Zilog with a different number, BE SURE they include ANY board modification instructions required to make it work in yours! ADI (800-228-0530) can also provide entire replacement boards. Note, the signal from the Zilog routes to the drive circuit through some digital-switch transistors; these are usually OK, but they test out differently from standard transistors.

QUESTION NO. P325-7: Four Sony GDM-2038 monitors all doing the same thing. They shift to the right and when first turned on, they are in a horizontal roll. After the monitor is on for 15 to 20 minutes it stops rolling and is fine, until after being on for long peroids of time (couple of days).

You have bad caps in the sync circuit.

QUESTION NO. P322-6: Gateway (Mag) 1572FS monitor that has a series of horizontal lines that appear to go from bottom to top in "waves". Is there a manufacture upgrade? Problem occurs from cold start. Before, only when warmed up.

Check for bad caps in the vertical circuit.

QUESTION NO. P319-2: Two AcerView 7176IE monitors that exhibit video smear (a ghost effect on text characters and icons). For example when when working with text documents the characters have a green tint and a light grey shadow to the right of the characters.

You need to readjust the crt beam centering magnets.

QUESTION NO. P318-10: Sony CPD-17SF2 monitor, dead. Replaced hot, now powers up, but shuts down with power+saving leds flashing, size led constant.

You have a shorted fet at the input to the flyback.

QUESTION NO. P49-9: I have a lot of CRT (different make and size-14" and 15") which have same problem- focus can not be adjusted properly and picture size-horizontal and vertical changing with focus adjustment. RGB guns emission is perfect. Most of CRTs are pretty new.

You are encountering power regulation problems. Your B+ should remain constant when adjusting focus or screen. It is also possible you have a bunch of bad transformers.

Get the High Frequency Generator model BD-10ASV (or another one- this is for 230V AC)made by ELECTRO-TECHNIC PRODUCTS, INC. (the address 4642 North Ravenswood, Chicago, IL 60640). It seems your problem is dirty CRT inside. Before using this generator for CRT focus cleaning connect CRT's Anode to ground- make a connection tool from old one FBT. Usually helps.

QUESTION NO. P49-3: CTX 6488ES on power up there is only a steady white horizontal line in the middle of the screen.

Troubleshoot and repair the Vertical circuit.

QUESTION NO. P413-2: Apple Multiple Scan 15 m/n 2978. What is SG305 on the video board? It glows brightly, while the other Sg#'s just flicker.

What you are describing is a spark gap. Some companies use neon bulbs for this. It is indicating that the crt is shorted on that gun.

QUESTION NO. P415-9: Compaq 151FS monitor, changes the color after 10 minutes from white to red. If the housing is open the problem is fixed. I have changed the power semiconductor of red-line, it was not helpful.

You probably have a bad processor ic and maybe a few caps.

QUESTION NO. P415-1: Gateway 2000 CS1776LE monitor. Several parts related to Hivoltage are gone. Q117 D799, Q116 IRF740, and Q109 C4747 (power out put high voltage) are shorted and C525 1/450v, C908 1/450v, C123 1/50v,and C123 1.5j are dried; ( Tested by ESR Meter).

You also need to replace C120 1uf/50v and the part that caused it all "L105".

When any of these parts dies, it takes out many others; all need to be replaced simultaneously, or the remaining bad parts will then kill the replacement parts. Besides replacing all the parts mentioned, you also should replace tall coil L105, C120 = 1uF; also R181 = 120K if its value changed. Since Q116 was shorted, also check R177 = 1 ohm and D116 = 30DF6 (on tall heatsink, NTE580 sub). This is a Mag chassis, L105 is p/n# T*I-281-103-UO; get it from Mag Innovision, or from suppliers like LJ Enterprises, 800- 627-8755, or NEI, 888-634-7278. On rare occasions, the CRT socket or yoke connectors are burnt inside, may be worth inspecting.

QUESTION NO. P416-10: Digital Philips FSR871CV. At the start the display is good, after a minute or so, the display becomes lighter and lighter and the desktop vanish.

You may have a bad ground connection on the IHVT or it itself may be bad.

The screen/focus blocks are a problem in this model. There are a few different versions; which version depends on which exact CRT is installed. If replacing it, you need the entire number off the one in your unit. In the US, LJ Enterprises, 800-627-8755, and MI Technologies, 937-335-4560, have carried them. For Europe, try ICHE in the UK, Phone, 044 (0) 115 932 0152; email, tony@iche.com.

QUESTION NO. P416-7: Dell D1025HE (FCC IEY447S). The height of the picture is too small (vertical), top is appr. at 50%. Perhaps this is a software problem? Can I give a general reset in some way? (The factory defaults menu option does not help.)

You need to troubleshoot the vertical circuit.

QUESTION NO. P416-6: What is the value of the hot on a Mag dx17f?

Your transistor is a 2sc4747 VCEO=800V VCBO=1.5KV AMPS=10, you can also use a BU2525AF

Depending on date of manufacture, Q109 is 2SC4747 (early) or 2SC5048 (later on). The DX17F chassis sold as Micron monitors sometimes use 2SC5129 as well. These transistors are fairly interchangeable, 10 to 12 Amp HOT's.

QUESTION NO. P329-6: Sony 15SF2 that immediately gets very bright and out of focus and then shuts down. I replaced the Flyback with no change. R494 measures OK at 680k.

The problem was a bad LM1207N on the CRT Socket Board!

QUESTION NO. P412-1: Hyundai HN-4850 monitor, FCC CKLHN-4850. C515 (22u@50v 85c) blown and R526 (47ohm 0.25W) burned. I replaced those and powered up unit with a variac slowly and C515 smoked again. I found 70V on C515. I subsequently found D581 (labeled T NH5) shorted. It is in series with D582 (labeled T 3JU). These appear to be damper across the yoke. The center connection diode junction goes pincushion circuit, I think ie to a TDA4950. The diodes I cannot find in NTE or ECG for a specification guess. Any other parts that may be blown that I have over looked so far?

"T NH5" and "T 3JU" are Toshiba rectifiers, but Toshiba often uses markings that are not precisely the rectifier's part number. The "T" means Toshiba, "NH5" is rectifier 0.5NH45, rated 1000 V., 0.5 Amp, Trr < 200 nsec; and "3JU" is rectifier 3JU41, rated 600 V., 3 Amp, Trr < 100nsec. You might try subbing either NTE575 or NTE558 for the 0.5NH45, and NTE577 or HER506 for the 3JU41.

QUESTION NO. P412-2: IBM 6543-305 (G50) monitor, dead. After replacing LM393 in power supply, the monitor works, but the bright control key does not. The other control keys are working.

Check R424, near the flyback, for value or open. If R424 is OK, see if that fragile ribbon cable assembly going to the user controls has broken, and needs replacing.

QUESTION NO. P323-3: Apple 1710 monitor (which I understand is a Sony monitor in disguise) and found the horizontal output transistor is shot. We replaced it but it is still getting too hot and still having pincushion problems and a too narrow picture.

Check QL2 (IRF9630), RL83 (10E), QL23 (MJW16012, I think). Resolder the transistors mounted on every heatsink. and resolder the cap's and coils in the PSU. Check pulses on QL2 (gate), if not there check QL1 (BC547) else replace IV11 (located on the video board LM392-SMD).

QUESTION NO. P331-3: Compaq 462 display monitor has failed with blown components: Q401, Q402, Q403, Q404, Q405, Q82 (Hor OP), R412. R412 has vaporised. Can you please tell me what value this is? Also Q404 is marked F423, I can not identify this device in all my data books, can you give me an equivelant device number. Also, can you tell me what value B+ is set to, and if anything is common to cause this domino effect.

If the "F423" has a TO-92 case, it is probably BF423, a Philips high-voltage PNP transistor. MCM (800-543-4330) & Union Electronic Distr.(800-648-6657; http//www.unionel.com) list it. For the other data, Compaq isn't likely to help, so check your FCC#. If it is FCC #BR8SM-1457, it is made by ADI, model# SM-1457, and you might try that model# to see if you can get that info from ADI tech-support, email, techsupport@adiusa.com.

QUESTION NO. P46-7: How do I remove the cover of a Dell D1025HE 17" monitor? Who is the manufacturer?

Like many other computer manufacturers (including Packard Bell, Compaq, Gateway, Apple, and more), Dell often uses the same model number for monitors that are different chassis, from different manufacturers. So be aware that if you post a question for any of these, and did not include the FCC number, any answers you get just might be for the wrong monitor chassis! To find out the real manufacturer, get the first three characters from the FCC number, and look up the manufacturer on the FCC website at http//www.fcc.gov/oet/fccid/.

QUESTION NO. P46-4: Packard Bell 1020 monitor works OK in 640x480. Video barely visible at 800x600 and above. All modes work OK on Checker 12E but not on computer. Tried on two computers.

Since you did not give the monitor's FCC number, I do not know which Packard Bell chassis you actually have, but on at least one of those models, the picture goes dim if run at too high a scan rate on the newer video cards. Try setting your computer's video cards for the old IBM 8514's scan rate, and see if the problem goes away.

QUESTION NO. P45-10: IBM G70 monitor 6544--403. I need a part # cross for Q872. The part is marked FQ161 replacing to fix green screen.

If Q872 has a TO-92 case, this is probably a Philips BFQ161, NPN video transistor, rated 19 Vceo, 0.5 Amp, 1 Watt, Ft >1 GHz; there is no ideal cross for this device. Arrow Electronics (800-833-3557) lists BFQ161 in its inventory, or you might try a Philips distributor, but the device is obsolescent.

QUESTION NO. P45-8: Acer 7154e monitor. Transistor K22161 and BU2520AF have died. What their analogues and characteristics?

I think you actually meant K2161, which is Q317 in this unit, a Sanyo FET = 2SK2161, rated 200V, 9 Amp, Rds[on]<0.35 ohm, 25 W., insulated TO220 case. A sub is IRF630 with insulating hardware. BU2520AF is a Philips horiz. deflection transistor, rated 1500 Vcbo, 800 Vceo, 10 Amp, 45 Watt, Tstg = 4.5 usec typical, Tf = 0.35 usec typical, DC gain (0.1 Amp) = 13 typical; SOT199 case, no internal damper diode. This transistor is readily available and inexpensive (in North America, at least); I recommend using the original type, but if not, possible subs might be Hitachi's 2SC5207A or Sanyo's 2SD1887. One source for all these is B&D Enterprises (800-458-6053). In this model, I suggest you also replace ceramic cap C335 = 220pF/2KV for this symptom.

The problem is also true for a HP monitor model D2825 (or ULTRA VGA 1024). The transistor 2SK2161 is equal at IRF630 or IRFI630.

QUESTION NO. P330-3: Packard Bell 1412SL, burnt out resistor R454. I need the value of this resistor.

R454 is a carbon film 1/4W 2K ohm +/- 1%.

QUESTION NO. P329-1: Packard Bell 1412SL monitor FCC# BJMCM14UP with an open D814. (Looks like it is in the power supply section). What is the problem and where can I get parts?

D814 = UG2D, an ultrafast (Trr < 25nsec) rectifier, rated 200V, 2 Amp. If your supplier does not have this rectifier, some possible subs are SF24, SF25, or SF26 superfasts (all 2 Amp, rated at 200V, 300V, or 400V). Mouser (800-346-6873) lists those as cat.# 583-SF24, 583-SF25, or 583-SF26, all <$1 ea. Or NTE/ECG576 might be used, if you drill open the solder pads a bit wider.

First check all fuses and replace if blown. If monitor still same then likely D814 check it, in my case it was a UG2D short circuited. However, when eventually managed to get replacement UG2D found that would fail due to overheating lasting just a few seconds. Replacement I found which worked was BYV27-400, also cheaper! So far monitor working fine after heat soak.

QUESTION NO. P42-5: Gateway 2000, Model CS1572FS has Horz. shadows much like mouse cursors trails but they do not go away. They are very noticable on icons and trail to the right of all open Window Boxes. All else works fine.

Gateway used "1572FS" for a couple of different chassis (different FCC#). Smearing to the right is relatively common, and can be either the CRT being bad, or problems on the CRT board. If the smear to the right is white, not colored, this favors a bad CRT. The units with Toshiba CRT's are generally bad CRT's, units with Hitachi CRT's are more likely to be smeary from bad CRT boards. In those, check the CRT boards for bad caps, transistors/ video amp IC, zeners, etc. In those chassis with R331, a 91K resistor in the power supply section, this resistor needs checking, because it can cause the CRT to die (and other problems) if its value is bad.

QUESTION NO. P330-10: Hyundai Model HCM-402c with loss of vertical hold. Replaced vertical deflection circuit ic, checked all capacitors and resistors with no change of condition. Everything else seems OK.

Can you check the signal cable?

QUESTION NO. P331-9: Acer 7154e 15" monitor. Transistor K2161 is dead. I cannot find it, what is analog and its characteristic?

K2161 is a Sanyo 2SK2161 FET, its characteristics are 200 Volt, 9 Amp, 25 Watt, Rds[on] <0.35 ohm at 4.5 Amps, in an insulated TO220 case. B & D Enterprises (800-458-6053) lists 2SK2161 for $2.90. Or use IRF630 with insulating hardware. For this fault, better also check C335, coil L304 (2 mH), D316 & D317 as well.

QUESTION NO. P325-4: I need a supplier for a chip ux051b0102 for an ADI SGVA monitor.

This chip is actually UX051B010Z, so your supplier may not have recognized the incorrect number. In the US, places like CCS/EDI (800-426-6423), LJ Enterprises (800-627-8755), or NEI (888-634-7278) often have preprogrammed uProcessors. If their price is very high, you might see if a whole new CPU card from ADI (800-228-0530) is available.

QUESTION NO. P325-2: CTX-1565D. Picture is very dim and has some smearing of text in all video modes. It appears that the brightness and contrast controls are working correctly. The CRT is made by Samsung and has the part # M36KUK35X15. Is it probable that the CRT is bad?

Dim, smeary picture in a Samsung CRT is very commonly a bad CRT. But before condemning it, check if the filaments have sufficient voltage, or if there is much AC ripple in the filament supply due to a bad filter cap.

QUESTION NO. P325-9: AOC CM-335 monitor. Line output transistor (Q405) replaced 6 months ago with C4769 (2SC4769??) has failed again. Is this the correct component for this monitor? Also is there any known historical reason for early failure of this component?

The AOC CM-335 has several different chassis versions, with differing FCC numbers. In FCC#ARSCM3352, the H.O.T. is Q405 and that one is 2SC4769. This H.O.T. may fail due to a bad horiz. drive cap C417 = 47uF/50V, next to T401, the drive transformer.

QUESTION NO. P319-3: TTX model TTX-3500 monitor. I need to know the following parts in the power supply which were missing: ZD 4,. D 15 and D 18. The unit was a mess, iIt had both p/s problems and a blown HOT.

ZD4 is a 1N759A (12v),D15 is a UF5402 and D18 is a UF5408. Just finished replacing these parts on a TTX 3500 . Check both Q612 and Q603. Both were shorted in my unit. Also, R645 (2.2 ohm) was open.

QUESTION NO. P317-6: Siemens Nixdorf Scenic Monitor PM 150 G5 S26361 K408 F516, FCC ID JVP71561S. I need a supplier for transistor TOP214AY1. I have tried most companys in the UK.

First, "TOP214AY1" (actually TOP214YAI) is not a transistor, it is a specialized power IC, that combines a PWM regulator with a power MOSFET, inside it. It is made by Power Integrations Inc, but since you are in the UK, I suggest you contact Sequoia Tekelec, Ltd., www.sequoia.co.uk, address Tekelec House, Back Lane, Spencers Wood, Reading, BERKS, RG7 1PW. United Kingdom. Telephone 0118 925 8000 Fax 0118 925 8020 Technical Help & Data Line 0118 925 8090 Technical Fax 0118 925 8060. You can read specifications, and a schematic using this IC, at this Sequoia URL http//www.sequoia.co.uk/Products/PI/top200.htm.

QUESTION NO. P317-7: NEC monitor JC-1733VMA which displays a green LED but no video. Items that checked good were heater, HV (stays on) and power supply output voltages.

Check the CRT board for a high-ohm resistor, I think R906, 1.5 Mohm, that goes bad.

QUESTION NO. P310-1: ASTVision 7N (KD-1711) with R916 & R907 near the flyback burned beyond recognition. I need their values.

KD1710, a similar model, has R907 = 10K/0.5W; R916 = 100K.

QUESTION NO. P316-3: DX15FG Mag monitor, width too wide - unadjustable. CPU is changing level while pushing width button. Caps tested ok ESR. transistors in horizontal section statically ok.

First check caps C105 or C106, 0.0068 uF, near flyback. If OK, is the VGA B+ voltage regulating at about 71 VDC and about 1100 Vp-p? If the B+ regulates OK, try tracing the width circuit; you may have a bad part or bad solder joint on that circuit. By "cpu", do you mean the TDA9103? This IC is a known problem, but if your IC's output is OK, as you say, then start tracing the width signal elsewhere. Try to vary the signal, using the + and - buttons, and check if it varies off pin 7 of IC102, then Q203, then C108, L106, L105, and on to the yoke connections. Note by the time the signal is reaching the coils and yoke, you may have Vp-p values of hundreds of volts.

QUESTION NO. P33-5: Je travaille sur un Sony 17" CPD-17SF2.Quand on le met en marche la THT demare la trame aussi,puis plus rien. Les tensions sur le secondaire de l'alim sont pr廥entent.Deux LED orange et verte clignotte et la led orange du r嶲lage de g廩m彋rie reste eclair� en permanence. Quelqu'un pourrait-il m'aider.

Check ta haute tension (frequence).

QUESTION NO. P29-2: ADI 5V model #LM1764 dead with good fuse. I cannot find much on it and Iam stumped.

Try checking H.O.T and if tests good check power supply. You did not say if there was any led flashing so this is all I can give on this.

QUESTION NO. P311-10: I need a source for parts for a Cushman ce-2b service monitor. The parts I am looking for are HPA0136 Snap Diodes ( or Step recovery diodes ). I need at least one diode to repair this unit.

Try RF Parts in San Mateo California. They carry a lot of unique RF parts. Phone number 1-800-737-2787 for parts and 760-744-0750 for technical help.

QUESTION NO. P225-4: Have a few NEC XV17 model JC 1734VMA monitors, FCC #A3DJC-1734VMA. Two units had poor focus that could not be adjusted with fbt pots. Replaced cracked fbt with good units, and now cannot properly adjust focus. Is there a secondary adjustment/part replacement to calibrate for new fbt?

If you can go from bloom to bloom you have a bad crt. If it is almost focused at one end, then you need to readjust the high-voltage regulator.

QUESTION NO. P34-4: NEC 3D monitor that when turned on just has a white line across the center of the picture tube.

Check for vcc at pin 1, 12volts. and for b+ at pin 7, 24volts. You may need to replace the LA7835 ic.

QUESTION NO. P310-10: Three Apple 12" RGB color monitor model No1296 with the same fault. The horizontal collapses about half an hour after it is turned on and then collapses almost staight away after it is turned back on.

You probably need to resolder the yoke plug. This is a common problem with this unit.

QUESTION NO. P310-8: Acerview 7134T (FCC ID #JVP7134T). No light on the power LED, the monitor is completely dead. Checked fuse, ok. Checked filter caps around power supply with an ESR meter, caps ok.

Check the H.O.T. You can pull it and see if the S.M.P.S. fires up.

QUESTION NO. P310-7: Maxtech XT-4800 with no blue drive. I changed the MM1203N checked all caps and resistors on yoke board without change. I believe this monitor is made by Samsung.

It is not the yoke board, it is the crt drive pcb. You can compare red and blue. Red in is pin 4, Blue in is pin 9. Red out is pin 25, Blue out is pin 16. Have you checked the video cable?

QUESTION NO. P218-6: TTX 3500 monitor with no horizontal sweep. Displays only a thin vertical line.

Replace the vertical output I.C. and/or troubleshoot the vertical circut and related supplys.

QUESTION NO. P310-3: Logix LG-143snie monitor with a faulty ic902 located on a small circuit bd used to power up the monitor when a video signal is applied. I need a replacement number for this component. Its only markings are a509 k12no 6l made by SGS Thompson Malaysia.

That "IC" is a logic-level FET, SGS# STK12N06L. You did not say if yours is an SMD type, or a thru-hole FET (it comes both ways). If you cannot find it, I suggest getting one of SGS's STD12N06L-1 (thru-hole), or STD12N06L (SMD), for example, from Mouser (800-346-6873, cat# 511-STD12N06L1 or 511-STD12N06L). If it is the thru-hole FET, it would be good to attach a small heatsink, if there is not one present already. These STD FET's are similar to the STK type, but the packaging is a bit different.

QUESTION NO. P210-4: I need the value of a capacitator C322 in an AST SVGA-LR14.

The component C322 has the markings "6n2 J 1600V Philips".

QUESTION NO. P223-3: LEO-1423A monitor from First International Computer, Taiwan. The screen has display but it is very dark (dim) even if brightness and contrast is set to full.

Check crt if Samsung that is 34kun at the begining of number these crts are famous for going bad. And you can not rejuvenate these crts. If not Samsung tube, check all voltages on crt board to make sure they are correct. If correct, then crt is worn out and maybe you can have it tested and try to restore it with a crt tester-restorer.

QUESTION NO. P215-8: Daytek 14" model DT14SNI no vertical deflection, only horizontal line in center of screen. Replaced vertical IC as well as repaired numerous bad solder connections. Problem still the same.

I would first check all caps in the vertical section. Heat can cause bad esr. Replace bad caps with 105 degree caps. Also check the yoke for possible short

QUESTION NO. P226-7: Samtron 428V+ monitor of which the horizontal size (top to bottom) is reduced. When I try to adjust the picture size, it does not go bigger than just a bit more than 3/4 of the screen and gets sort of flyback lines at the bottom part of the screen, almost like a foldover. When I adjust the picture location, it does the same thing when I try to adjust the bottom part of the picture below 3/4 of the screen.

The Samtron problem is the vertical defection ic it is a tda series inline ic.

QUESTION NO. P127-7: Aiwa CX-999U. The display is extremely dim. I do not have any of the specs and no voltages are marked. The florescent display, if it is like every other, should have ~3V AC from each side and ~(-25V) DC on each active pin of the display. The AC is there, but I am measuring 3~5V DC on the active pins. Is this common? If not, where does the display voltage come from and what should it be?

Check -33v line one filter is open.

QUESTION NO. P226-6: AST 5L FCC# GKR562D that has blotches on the CRT. Looks like a magnet was held next to it for too long. Is it worth buying a manual degausser for this?

Take a weller or equiv. soldering gun. Turn it on, rotate and slide it up against the blotch on the tube face for 5 or 6 sec. (watch the hot tip). Withdraw the gun leaving it on all the while. When 2 or 3 ft. away, turn it off. Done.

QUESTION NO. P226-8: Compaq model 620 monitor, fcc id BR8SM769. It has a good display, but when the display changes contrast level, horiz width changes, sometimes it will pull in a couple of inches. Looks like voltage regulation to me.

Try replacing the high-voltage electrolytic cap just outside the flyback cage. That cap can give these symptoms when bad. If it is OK, then check the B+ regulation.

QUESTION NO. P225-2: IBM 6540-00N monitor. No screen, LED is on, have high voltage(25Kv), tube neck doesn't light up, 0v at heater. Capacitor between the two heater lines says 223Z on it, What value is this? (223pF?)

The value is 0.022 uF. See the answer to question# P216-2, on the TV repairs answer page, for the details on reading these capacitors.

QUESTION NO. P218-7: Acer 1772e monitor. R239 is burned, I need the value.

R239 = 0.5 ohm/0.5 Watt/ fusible. Also check Q311.

QUESTION NO. P223-1: NEC Multisync monitor model no. JC-1734VMA. I need the value of Q541.

Q541 = 2SC5047. Before replacing Q541, check if Q572 = P-FET (2SJ306 or 2SJ307) has gone leaky or shorted, or else high B+ voltage may blow your new HOT as well. Also be sure R538 on main board is not accidentally touching and shorting to the shield. Parts available from MCM (800-543-4330), or B&D Enterprises (800-458-6053).

Q541 is marked C5047.

QUESTION NO. P222-10: Several Magitronic computer monitors. Model number is C-SV1448. Fcc ID# is H41CM14005. Where can I buy L802 at. These Coils go bad causing the HOT to blow.

Your FCC# actually starts with H4I, not H41, which makes Lite-On Technology the manufacturer. In the US, you can try Lite-On at 408-946-4873 or 408-946-1751, or else try L.J. Enterprises, 800-627-8755, another source for Lite-On parts.

QUESTION NO. P29-4: What is the value of Q427 on the main board of an AOC model 7Hlr?

Answering my own question, I finally found a service manual for the AOC 7Hlr monitor. Q427 is a BU2525AF.

QUESTION NO. P216-10: NEC 4FG 15" monitor with a focus problem. I can adjust the focus but it will change and need to be readjusted. It constantly changes.

You need to replace the flyback, they are known for this.

QUESTION NO. P119-9: MAG DX15F monitor Q502 bad, need value?

Value of Q502 on DX15FG is 2SC-3198Y.

QUESTION NO. P114-9: Apple multiple scan 17 display model M2494 made by Sony. Someone has removed the FET location number Q505 I need the generic number for it.

Q505 = IRFI9630.

QUESTION NO. P211-9: Wen monitor Model JD144L which came in with the power supply "tripping". I found that the HOT was faulty and replaced it with the original BU5208DF. Before powering up I checked the power supply output to the HOT and it was 81 or so volts - I assume that is correct, so connected it and I powered up and it blew again. I have checked every diode and capacitor around the flyback and I cannot come up with a thing. I am suspicious of the flyback, but I am unable to source one here to prove it. Monitor flybacks in South Africa are scarce.

Check for a shorted flyback drive F.E.T.

QUESTION NO. P212-10: Three Apple 12" RGB color monitors Model No M1296X. When first turned on, everything works ok but after about half an hour the horizontal collapses and the screen goes blank. When turned off then on again, the horizontal collapses very quickly. The problem would appear to be a common problem with the three.

You have bad connections on the yoke plug. Check the horizontal circuit in general and also check the video drive ic.

QUESTION NO. P210-1: HP 4033a monitor (fcc id# ak8gdm20e01) which was dead. I replaced two shorted transistors Q510 and Q 511. The units high voltage comes up for a second and the unit goes into shut down. The amber power save light and the green power light blink together. Everthing checks ok , I supect the fly back.

On this Sony chassis, the blinking LED's indicate a shutdown, but there are several causes of this. It could have helped to indicate which LED's were on solid, as well as which are blinking, to narrow down the possibilities. Given that Q510 and Q511 were shorted, check these other common failure parts Sony small white fuses, PS500, PS501, PS800, etc. (SOC1000 or SOC1600 = 1 Amp or 1.6 Amp, can sub Picofuse types); C822; R868; D824, D825; IC404 = TL082 dual JFET opamp, IC801 = 4049B logic IC. Also test any diodes from gate to source off of FET Q511, these may be zeners (like D504, if present) for gate overvoltage protection and/or Schottky (or germanium) types, for voltage-reversal protection.

QUESTION NO. P29-5: Apple multiple scan 15 (model M2978) out of horisontal sync. I have changed TDA9102 without success.

Most likely, the problem is a cheap fix, replacing IC951 = 12 Volt regulator IC, if it is not outputting 12 V. correctly. If that is not the fix, check transistors as you trace from IC951, until you reach the pin on the TDA9102; if these are also good, try replacing hybrid IC501 = HIC CQ465 (contact a Goldstar supplier for this).

QUESTION NO. P114-4: Compaq Qvision200 model 480. The unit comes up with a vertical sync out of range error then a high voltage failure. I have tried several scan rates up to 1280 by 1024 with he same errors. The vertical and horizontal pulses are getting to the yoke at the correct frequencies. Checking by means of schematics I appear to also be getting both horizonatal and vertical failures. The signal common to both of these is the blanking pulse which is about 4.4 volts peak to peak. The signal after a divider is only about 0.75 v p-p. What level signal should I see at this point ( the junction of R889 & R904)? Q860 and Q861 have been changed with no improvement. The manufacturers of these monitors are at best unco-operative.

Check L807.

QUESTION NO. P113-9: CTX vl500 with a loss of video and shutdown after 10 seconds. This monitor came in with a busted connector on the video cable. A possible short in the video circuit?

It is possible, but first make sure that you are getting Horz. and Vert. Sync into the unit. Without them the set will not fire up.

QUESTION NO. P18-1: Gateway monitor, model YE0711-01. When I power it up, a relay begins to click on/off continuously. From time to time I was able to power it up by tapping on the circuit board, thinking that it was an intermittent problem. This process has now proved me wrong because I cannot get it to power up anymore and the relay continues to click. I have read that another of these had a similar problem and it turned out to be the flyback.

First recheck any resoldering that you did to make sure you did not bridge any connections. If that fails, try the flyback.. Have you checked the H.O.T.?

QUESTION NO. P25-1: Packard Bell 1020 that went dead. It sounds as if it is in HV shut down. Repaired all broken solder joints and replaced two resistors. No LED activity on the front, just the tic tic sound.

Cheched the H.O.T. it is the most common cause of the TIC TIC sound.