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| QUESTION NO. P220-10: RCA Projection TV P46050T frequent intermittent picture shrinks to narrow band. Horizontal transistor OK. Plan to replace caps but L906 burnt, need value / part no. |
| Value is 100uh, RCA part no. 150169. Also replace C904, C908, maybe HOT problem as well. |
| QUESTION NO. P130-7: Toshiba TN50v71 projection TV has convergence problem on top only. The two ICs have been replaced. I do not know the sequence to get to the service menu. |
| For info on entering service menu, go to http//members.accessus.net/~090/awh/how2adj.html#5.2. |
| QUESTION NO. P218-2: Sylvania Projection TV has no power. Another repair guy had replaced the fuse with a 30Amp car fuse (bad.) The power resister on the line board with the fuse was torn, and jumped. I found that the foil line was burned, and transistor BUW12A or Q10 was shorted all BCE. 0.00 When I replace this, will it blow again, or what else should I check that might have damaged that transistor? The HOT tests good, so does the Damper Diode. |
| You must change BOTH Q10s. One is on power supply, other on sweep. Transistors are different. Putting that 30amp fuse in was not very smart. Main power supply load resistor is probably open ,1.8ohm/15watt or similar. Who knows what additional damage may have occurred? Check foil traces for opens. |
| I found open resistor, found burned foil line on PS board, I replaced both. Found both Q10s shorted, replaced both. Replaced the diode on Deflection panel, and checked Q11, D13 on PS panel, and were NOT shorted. I replaced all of these, and the set kicks on for 2 or 3 secs, and kicks off, but the Power LED in front stays on. |
| QUESTION NO. P125-6: Zenith projection TV main chassis no. 9-1874-2. Dead set, R3252 burned. Replaced but still dead. H.O.T. ok. |
| I think you mean 9-1674. When R3252 opens , typically Cr3215 is shorted. |
| QUESTION NO. P1217-4: Zenith PVY5263DT Projection TV Convergence cannot move horizontal lines in "Projo Setup" menu up or down. Was able to move Red and Blue down (but not up) but they now seem locked. Can move vertical lines left and right OK - both Red and Blue. Replaced Registration Module (009-01690) but this didn't fix problem. I've been told to reset TV to factory defaults by disconnecting from mains (while On) for 30 mins but this doesn't seem to clear the menu settings, channels, etc. Nor does it allow the Convergence to be fixed. Also, blue CRT seems to be slightly out of focus. |
| You may be missing a +/- supply voltage to the convergence panel. At connector 7C3 check the following pins Pin 2, +26vsw; Pin 3, -26vsw, Pin 4, 16vdc. The 16vdc is regulated by IC 4006 to +5v. The -26vsw. is regulated by IC 4007 to -5v. If one or more voltages are missing at 7C3, they are generated in the power supply panel. The +26vsw. is protected by FX3460, a 5A fuse and output thru CR3419/L3408. The -26vsw. is protected by FX3461, also a 5A fuse output thru CR3420 (checked at anode end) and L3409. The parts for the +/-26vsw are located to the left of TX3402 as viewed from the top. The 16vdc comes thru RX3210 (1ohm, 1/2w) and CR3206 located to the left of TX3204 and behind the H.O. xister. Also, the blue tube is purposefully adjusted slightly out of focus to give a better over-all color picture. |
| QUESTION NO. P1120-4: LXI (Magnovox) 626.54461850 projection TV, replaced blown fuse. Set starts to power up about 2-3 seconds then relay clicks off. Everything off except LED's on front. Found shorted Q-10 transistor on Deflection panel. Replaced both Q-10s (Deflection panel + Power supply) with no change. I then found an open power resistor (1.8 ohm 18watt) on the A/C Panel. I temporarily replaced with a 1.8 10 watt (having trouble locating 18 watt) now the set turns on with sound but no picture. The bottom of guns are glowing but the tubes are not lit. |
| Check for short on 130Volt line. With the set unplugged clip the negative lead of your DMM to TP3 (Hot Gnd.) located on the Power Supply Panel. Connect the positive lead to TP7 (130 Volt source). Reading should be >100k. If a short is shown--and with test leads still connected--unplug P108. If still shorted, problem is on power supply panel. Check Q10, Q11 and D13. If unplugging P108 removes short, check for shorted Q10 and D14 on the deflection panel. Important!! Replacing either panel without following this procedure will short out the new panel installed. Often, both panels must be replaced at the same time to avoid one shorting out the other. This is the most common problem on the PTV 310/325 chassis. Part number for 1.8 ohm 18watt resistor is a Phillips part; 2401180002. |
| QUESTION NO. P1120-6: GE PTK195AA projection TV can work fine 5-10- 20 minutes or even hours then it will have problems with convergence. I checked the B+ and B- going into the convergence board and seems to be ok. The connections were resoldered. Since this model doesn't have any STKs devices do I really need to buy the whole convergence board? |
| home.mindspring.com/~wa6ati/195-197.htm |
| QUESTION NO. P1129-7: ctc-169pg projection TV has no power, it just has a high pitched type click. |
| home.mindspring.com/~wa6ati/Ctc169.htm. |
| If what you describe is a constant clicking sound when you hold the power on button, is the sound of the start up voltage being cycled on and off by the hold down or shut off system in the set. Check the HOT circuit in full. The problem is the HV Splitter located under the frame around the CRT's. To verify this, pull out the feed line to the splitter from the Fly Back X former. Insulate it with a nice thick towel and fire off the set. If the set locks on and you get your 145 Volts at pin 1 at the FLY BACK. |
| QUESTION NO. P126-2: GE PTK 195AAprojection TV chassis ctc195, picture is bowed down on top and bowed up on bottom. I resoldered the convergence board and the tuner grounds connections and no luck. Do I need to replace the convergence boards? |
| home.mindspring.com/~wa6ati/195-197.htm. |
| QUESTION NO. P125-1: Sony kp61v25 projection TV has sound but no picture. Sleep timer flashes on and off all the time. Crts are not on but power is getting to them. The problem started a year ago with the picture turning blue then back to normal after a few seconds then to picture blanking out for a minute. Had to turn set off then back on to regain picture. |
| The IK circuit is killing the video, set is designed to do this to protect the tube(s). Take it to a tech that is familiar with Sony projection, you may have a bad tube, HV splitter, etc. Sony projection units are not a place to start for novice techs, if you must play with it yourself be SURE to use SONY parts NOT generic replacement parts. |
| QUESTION NO. P1129-10: RCA CTC169 Model P46160WK projection TV, Q401 Horizontal transistor keeps blowing. Set will stay on for 3 - 5 minutes before it blows even with the HV wire to splitter unhooked. Cannot find shorted diode or anything else unless overlooked. |
| I always replace high voltage caps C4401 and C4402. They are famous for causing the horiz out transistor to blow. Also, use the RCA part for the caps and the transistor. |
| QUESTION NO. P1116-8: Sony KPR-46EX32 projection TV, red gun projects a sharp horizontal line across the screen, about a third of the way from the bottom. Below this line there is no red picture projected. After about 20 minutes a red horizontal line flashes across the center and the video shuts down completely, but sound continues. After turning off TV and waiting 10 minutes, TV will project video for a shorter length of time, then repeat the problem. Red convergence also a problem at the top corners, but fine in the center. |
| home.mindspring.com/~wa6ati/ then go down the page and look for Sony TSS logs. |
| QUESTION NO. P1029-2: Sony kpr-53ex35 projection TV, after a warm up of around 1 minute, the red shifts all over screen, but the bottom right quadrant of screen is really bad, tends to fall off to the right and down. |
| home.mindspring.com/~wa6ati/ then go down the page and look for Sony TSS logs. |
| QUESTION NO. P1025-5: Mitsubishi VS-5062 projection TV, the picture rolls constantly via cable, antenna.and line in inputs. The menu does not roll. The PIP is black but can be swapped with the vcr tuner and there is video but it rolls. I found a leaking cap C-526 on the main pcb near the v-height,v-lin and hv reg pots. Would this rolling be a defective PIP board or on the main board itself? On darker pictures the rolling would stop as when a commercial is fading out and is worse with a bright picture. |
| Remove the PIP board and replace C7001=4.7UF,35v and all of the smt electrolytic caps on that board. Clean the board with alcohol. For more info refer to the tv archived section of this site where many Mitsubishi & Electrohome tv's equipped with PIP boards have this problem. |
| QUESTION NO. P1024-8: Sony KPR-53CX35 projection TV. Need to get into the service menu but all codes I have tried by remote do not work. Also checked back of TV for the small manual button that older Sony's sometimes have but this one does not have one. |
| Try sitehome.mindspring.com/~wa6ati/Sony-id.pdf. |
| QUESTION NO. P116-10: Mitsubishi VS-455RS projection TV has no picture or sound from the tuner. Both Aux inputs work fine with a video source. I replaced the tuner with no effect. |
| Does this model have PIP? If so, the trouble is leaky surface-mount electrolytic caps on the PIP board, especially any 4.7uf and 10uf components. Look carefully under these caps for corrosion/trace damage. Best way to test them is with an ESR meter, or replace ALL of them! ( Sync, both vert. and horiz., goes through the PIP board at all times, regardless of the PIP function being used or not. ) |
| QUESTION NO. P1121-5: Mitsubishi VS-4003R projection TV will not power on. Relay K900 clicks, but no audio or video. Solder joints were recently re-soldered. |
| www.circuitwork.com/techassist/tip/PROJECT2.HTM. |
| QUESTION NO. P115-9: Sony KP-53v15 projection TV does not turn on. When plugging in two clicks can be heard. There was one blown fuse on the convergence board. I replaced it but there is no change. |
| Replace convergence chips. Check for shorts and replace diodes for power supplies to convergence board. |
| QUESTION NO. P1023-1: Zenith PRO-900 projection TV shuts down at different intervals, and will not turn back on unless the power is completely disconnected for a short period of time. Just before it shuts down the picture starts to pull in at the right and left edges indicating to me that it maybe a high voltage problem. Also can you tell me what the 4 green leds on the 9-1515 RGB controller board indicate? There is no description in the Zenith schematics as to what these mean. |
| The top led indicates 5vdc is present in the 9-1515, 2nd led implies horizontal deflection yoke drive is present in the 9-1505, 3rd led is for the vertical deflection yoke drive present in the 9-1510, bottom led implies high voltage is present in the 9-1504. The 9-1504, 9-1510, 9-1505 and the power supply modules each have individual leds to indicate proper operation. |
| QUESTION NO. P831-2: Zenith PVY4662DT projection TV gets video and sound but I cannot get the colors to converge. The colors will not adjust at all, but the red and green jump up and down all the time. Also the colors are pulled off the right side of the screen. |
| If the menu does not work, your problem is most likely a defective R3243 (110k 1/2watt) located near horizontal yoke connectors. Otherwise check the convergence module 9-1690, for open 1 ohm resistors. Located near large heat sink. |
| QUESTION NO. P817-4: Zenith PVY5265MK Projection TV. The convergence adjustments do not work properly. The blue convergence moves slightly right and left. Red convergence does not move at all. |
| If vertical line is yellow (red missing) and not white like horizontal, in customer convergence adjustment mode, replace Red CRT board. |
| QUESTION NO. P730-3: Mitsubishi VS-5071 projection TV has no picture, but receives sound fine. The tuner works and the menu is accessible. Would the problem lie in the vertical circuits or the PiP module? |
| There is a quick test you can do to determine if the problem is in your PIP module, using two 4.7uf/50v electrolytic capacitors. The PIP module plugs into two connectors on the main board. Remove the PIP module, and on connector VP on the main board (the 11 pin connector), use one cap to jumper from pin 7 to 9 (negative lead on pin 9); and use the other cap to jumper from pin 5 to 11 (negative lead on pin 11). If the PIP module is bad, you will now have video. The PIP module has surface mount capacitors that go bad. Typically all but the three large surface mount capacitors will read bad or weak with an ESR meter. When you remove the caps and clean the board, check for eaten traces; especially around the 4.7uf/35v cap at the upper left of the PIP module. Sometimes the electrolyte leakage will also eat other traces, so be sure to inspect the area around the micro. I prefer to replace these surface mount caps with miniature leaded ones as they don't seem to have the leakage problems associated with the surface mount caps. |
| QUESTION NO. P710-9: Sony KP-53XBR45 projection TV picture had severe intermittent vertical pincushion symptoms. Pincushion problem stopped and picture now exhibits good convergence in center, bad convergence at perimeter. Straight vertical picture lines are displayed as wavy lines- horizontal scan lines look shifted relative to each other. Vertical compression, bottom 3" of picture missing. Fuses on convergence board OK. Have not replaced STK ICs yet. |
| The vertical drive signal was incorrect. This signal originates on the M board from IC3005 (CXA1477AS), the Luminance/Chroma/Sync (Y/C/J ) Signal Processor. Replaced this part and set now works fine. |
| QUESTION NO. P717-3: Zenith Z56Z83 projection TV has no high voltage, no picture. Power LED turns on. Replaced bad horizontal output transistor, but no change. Flyback tests okay. New HOT is still good. |
| Check CR3412, if shorted, the flyback is bad. Common failure on Zenith. |
| QUESTION NO. P710-8: Toshiba TP55G60 projection is dead. Relay clicks on and immediately clicks off. Power LED blinks. All standby voltages look good. Can hear high voltage come on and die. Varying the input voltage using a variac was of no help. Relay cycles at about 80 - 90 volts. Heard a snap ( similar to a cap discharging) and the set started working the next time it was turned on. Power cycled twice and set continued to work. Shut off the set and turned it back on a coupe of hours later and the set was dead like before. Waited 10 minutes and turned on the set. Again heard a snap and the set started working. Shut the set off and turned it back on - set dead again as before with relay clicking and momentary presence of high voltage. Hv regulator is Q483 - IC TA755585. |
| The flyback is arcing to the core. Replace it before you cause extensive damage. |
| QUESTION NO. P75-8: Zenith b50m88w projection TV. I cannot activate the convergence adjustment grid-does this set have one? |
| This is a Hitachi made TV for Zenith. Only customer access to convergence is through the PROJO SETUP option in SETUP menu. Otherwise a crosshatch pattern needs to be applied. Adjustment controls are on convergence correction module. |
| QUESTION NO. P67-4: Toshiba tp48e50 projection TV shrinks after 2 hours. It recovers by turning it off & on. |
| Look for bad connections on power/deflection circuit board. Have seen this on several Toshiba's. |
| QUESTION NO. P614-1: KP-46S15 projection TV, original problem was no picture or sound. Blown fuse on D board. Replaced both STK392-010 and both fuses which corrected the problem. New problem is double lettering on the left and right side of the screen in green and pink. The center of the screen is OK. |
| Look at resistors mounted under the heat sinks that the STK's are mounted on. Bet several have opened or changed in value. |
| QUESTION NO. P417-7: Sony KP-53V15 projection TV has sound but no image. |
| Check the convergence board for blown fuses or multiple broken solder connections, if the fuse(s) are blown you will have to replace them AND both STK`s on the convergence board, use SONY original parts or it will fail again. |
| QUESTION NO. P426-8: Sony KP-41T15 projection TV, when powered on, the picture did not come on and the timer/standby led keeps on flashing. If I keep it flashing for about 5 minutes, unplug the power from the electrical out let then plugged it back in immediately, the picture will come on after flashing exactly 10 flashes. I checked the power supply for any abnormal voltages that sent to the high voltage protection circuit to shut down, but everything looked normal. |
| Sony has incorporated a self test circuit in their newer televisions, both direct view and projection. The indication that this circuit has found a failure is the STBY light blinking on the front of the TV. Call for a fax on how to troubleshoot this circuit 900-555-7669 for non authorized service centers. |
| QUESTION NO. P413-9: Sony KP53XBR35 projection TV, the convergence is perfect in center of screen but the outer edges are all out of wack -All three guns. Replaced two blown 3.15 fuses on the D board but no help. |
| Anytime those fuses are bad you MUST replace both of the STK`s on the convergence board. Do not check, just replace them both at the same time (they are not cheap). |
| QUESTION NO. P49-10: Zenith PRO900 projection TV runs fine with no signal, but shuts down after 5 minutes with video. If powered up again while warm, it shuts down sooner. Power supplies under lenses all stay on. At time of shutdown, bottom green LED on control board goes off, top three stay on. Red LED on daughter board of flyback PCB goes on also. Unrelated problem Lower left corner of picture is curved w/ bad convergence, rest of picture fine. |
| When the bottom led is out, this implies fault on the high voltage module. Look at solder connections to all transistors mounted to the giant heat sink, especially the ones near the edge by the high voltage transformer. That transistor on the edge supplies horizontal drive to the high voltage switching transistor. |
| Follow up: Solder already checked throughout unit. Most caps in HV assembly check OK. Found D4924, D4927 open - need cross for these diodes marked "67". |
| QUESTION NO. P322-1: NEC PJ-4655EN projection TV, the picture is dark and there seems to be no way to brighten the picture. The "sharpness" button does not appear to work. |
| Do you really want to put 3 crts into this set? Probably where the problem is, unless one of them actually has lost its coolant all over the signal board. Both problems very often on these sets. Be advised NEC does not supply and parts or technical backup for these products. |
| QUESTION NO. P39-6: Zenith RZ46Z83D7 TV picture went dead but audio stayed on for a couple of seconds before going off. Replaced blown fuse,blew again. This time R3413 burned to a crisp. Need the value of this resistor. |
| R3413 is a 47ohm resistor. Most likely a shorted QX3402 is causing the resistor and fuse failures. ICX3401 may also be damaged. |
| QUESTION NO. P37-7: Sylvania rsh432 ak07 projection TV works good but it looks like the blue gun is bad. The red and green guns were already replaced and there is no remote control. I need a source for a manual, blue gun and remote control. |
| Sylvania is owned by Philips Consumer Electronics Parts 1-800-526-9354. |
| QUESTION NO. P226-1: Zenith Z60Z83 projection TV has little or no RED. The EHT and heaters or OK. The part number for the RED tube is EIA P15AHA00RF Zenith 100-815 replacement A-17649-51. I need a source of supply for this tube in the UK. I am also looking for what else I should check before condemning the tube. Should I change all three tubes? Also, if the mirror is attached to the rear of the case and I wish to adjust the tube lenses how am I supposed to get at them to make this adjustment? |
| Problem most likely is a defective R5102 (120k 1/2w) resistor on the red video board 9-1303-05. Replace with a carbon resistor instead of the film. If red is missing from the VERTICAL line in the projo setup position, this will cure your problem. Same resistor fails on the green and blue video boards causing similar symptoms. |
| QUESTION NO. P31-2: Pioneer sd-p5073 projection TV with no tuner reception. Auxillary inputs ok on video & audio. Used tuner sub with no response. |
| Right behind u\v tuner is an if pack in a metal case. Remove it & replace 2 .47 mfd caps at 50 wv. Reinstall pack. |
| QUESTION NO. P226-9: Zenith zb4685-bg projection TV ,main board#9-1225-r. I know that QX3208{board loc} is the HOT but cannot cross. The number on the Trans. is TZ 1167-01. I also need a cross on what I believe to be a V-regulator. Board loc QX3407. Number on trans, 1250. Flyback rings good. Any other suspected areas to look for? |
| The TZ 1167 is a 2SD2539. I just received one of these from Zenith today. |
| QUESTION NO. P226-10: Sony kp 53s35 projection TV, when first turned on timer standby light blinks off and on relay clicks off and on. When ant is disconnected the standby light goes off, and there is snow sound and a momentary flicker in the crts. Sometimes the sound will come and stay on with no picture. |
| After further troubleshooting, found vert IC, and IC protectors bad. Set worked find after replacing. |
| QUESTION NO. P29-10: Hitachi 50UX22B projection TV. Turn on TV and a colon () appears on screen about 6 inches left and down from top left corner. Change channel and it disappears until turned off and back on. Went thru complete setup routine but found no way to make it disappear. Setting the clock activated the clock down in the lower right corner. When TV is turned on, it comes on in lower right corner for about 30 seconds then goes off. The colon in top left stays. Microprocessor or some setup routine to disable the colon? |
| In answer to my own question, the colon in the top left of the screen was an un-erased message left either by fooling around with the remote or a message that was started and not completed. This set has a capability for two family messages that can be left. To erase, CLOCK menu, then clear messages from MESSAGE menu. |
| QUESTION NO. P15-4: Hitachi 53FDX01B projection TV, when performing a convergence adjustment with the on screen program, the red tube can only be adjusted up/down and left/right. Unfortunately, the red tube need to be twisted about one or two degrees clockwise. How is this performed (potentiometer adjustment or magnet adjustment)? |
| Your set needs a professional alignment, take it to a service center. DO NOT attempt to converge a big screen if you don't have the service manual AND the knowledge to do the alignment, you will only make it worse and it will cost you more to get it fixed. |
| QUESTION NO. P112-1: Magnavox 7p5441 c101 chassis ptv780-ah01 projection TV runs fine for three or four days then there is a loud pop and the HOT shorts. |
| Resilicone anode leads. |
| QUESTION NO. P1221-9: Toshiba tp-4688 projection TV, to turn on it must be unplugged, wait then plug back in. Turns on picture is fine, turn it off may not come back on until unplugged again. I checked capacitors on the primary and changed the main regulator. |
| Try to double check the electrolytics in the power supply. I think it was C840, C822, and C841. Also those units had a problem with leaking pix tube coolant onto the PCB's and that caused all sorts of unusual problems. |
| QUESTION NO. P1220-10: Mitsubishi VS5043 projection TV. HOT was 3-way short. Replaced, and new one fried instantly. High voltage circuit is OK. +135V supply is fine. Checked all components in circuit around yoke and this transistor with LCR meter. Tried running circuit at 60V with lab power supply, with 1 Ohm series resistor to monitor yoke current. I/V waveforms look fine at 60V with all three yokes connected. With normal connection to +135, HOT and 4A fuse blow in a second or two from power on. Fuse and HOT also blew instantly when HOR yokes were unplugged. Maybe this is normal? Maybe yoke or component near transistor that shorts only when higher voltage is present? |
| Problem ended up being L5A01, 3 mH inductor in series with +130V power supply. Replacing this part restored normal operation, and the H-OUT transistor no longer fries itself a few seconds after power on. I guess this inductor was shorting at normal operating voltage, although it seemed to work fine when we ran, the circuit at about 1/2 of the normal voltage. |
| QUESTION NO. P1218-8: Pioneer SD-P5183 projection TV. The blue convergence keeps going out on various intervals. The blue bows on the upper left of the screen. From time to time, it seems to come back in alignment by itself. Either at random or usually after the projection TV is turn on or off. I could not find any bad soldering connection. |
| The solution was to replace first the STK4277SL which was the cause of the blue bowing at the top. In addition, I encountered a second problem which manifested itself in the green loosing its convergence and at the same time resulting in two resistors to get toasted near the STK4274. I replaced the STK4274 and that resolved the green issue. After redoing the convergence on this SD-P5183 this projection TV looks great. |
| QUESTION NO. P1128-9: Magnavox RJ8510AK03 projection TV has no picture or sound. Suspect bad power module. Flyback seems to be producing HV and 40v. K1 relay (takamisawa 913684) seems to shut off shortly after power up. Get high-pitched deflection whine. Heat sinks on power module get "plenty warm." No visual indications of power module component failures. No o-scope or Variac available. |
| Change Q10 on the power supply panel and Q10 on the HV panel AT THE SAME TIME! Replacing one and powering up the set will immediately short the new Q10. |
| QUESTION NO. P111-9: RCA ColorTrak 2000 projection TV Chassis CTC132A. I need info on substituting the power transformer. The primary tests open with ohmmeter. Replacement part number would be nice, if not, the output voltages of this transformer. Three wires, red, green, and red with green comprise the output side of the transformer, the green wire appears to be a centertap. The three connect to the main board at locations SBC (green), SB1 (red) and SB2 (red with green). |
| Try Radio Shack P/N 900-5830 26vct 2.0A. |
| QUESTION NO. P1019-6: Am trying to find a source to cross reference Zenith part numbers for a projection TV sold by Sears. The numbers are like the following examples. 121-1250 or 121-1295. These numbers come from the Zenith schematic. |
| Zenith at 800-243-0000. |
| QUESTION NO. P922-1: NEC PJ4600EN projection TV was brought in for cleaning. Gray spots appear on the left and right, in 'globs' approx. 5 inches around, one on the left, one on the right-bottom, and one on the top. I can still see through the 'globs', but the picture is gray at that point. |
| Check with the customer to see if this unit was being used with an electronic game unit. I suspect that it was, and the "game" display has damaged the CRT phosphor. This is a common problem with projection sets. Electronic games should NOT be used on a big screen sets! |
| QUESTION NO. P914-1: RCA PMR 500 CTC 132 Chassis projection TV. I need a source for RCA part # 173494(H.V. dist. box). |
| RCA no longer supplies the part number ( 173494 ). Your best bet is to start calling all the local suppliers in your area, and checking with them to see if they have a used one they are willing to part with. There is no cross for this component that I am aware of. |
| QUESTION NO. P106-2: Zenith PV890X projection TV lost picture and power. Replaced power supply and deflection unit, still not working. |
| Check the HV/Focus Block for fine cracks allowing leakage of current to earth. New part actually as a modified, hopefully more reliable, version. Same part # as original but different configuration, comes with mounting bracket and instructions. |
| QUESTION NO. P911-7: Philips Magnavox 7P6041C projection TV Chassis PTV-780-AH01. Died, smoke coming out the rear. No fuse was blown. Found Capacitor C811 has burnt out. It is next to Transistor Q802. Is Q802 the Horizontal Output Transistor? |
| C811 is a 330pF, 2KV, 20%, ceramic capacitor. The original replacement part number is 483512247058. Q802 is part number 483513048074. It has been verified that the generic number is 2SD2539 which is a Toshiba transistor. Both parts are around $5 each. Both/all can be ordered from MCM Electronics. |
| QUESTION NO. P915-8: GE projection TV Chassis PTK169PKA that has good audio but the picture is really bright and has retrace lines bowed across the screen. All other functions work OK including OSD. |
| Try adjusting the SCREEN button (is located on the FBT, together the FOCUS button). |
| QUESTION NO. P724-8: I just replaced the Large Signal board on a Magnavox PTV 745-AH01 chassis. Now there is a problem with a 2" black band around the entire image as if the picture is smaller than the screen and also there is an hourglass effect on the right and lefthand sides of the screen. The color convergence is fine and the remainder of the picture is fine. Also, is there a service menu on this set as many other Magnavox units have? |
| If the yoke plug was disconnected before you hit the power on button, it would make the pincushion coil in the horizontal circuit so hot that you could not touch it. It also could short out the PCC transistor. Check coils and transistors in the horizontal circuit for extreme heat after it has been on for only 20 to 30 seconds. Check horizontal section transistors for Collector to emitter shorts. |
| QUESTION NO. P728-6: Mitsubishi vs-5020r projection TV will immediately power off when power button is pushed. Shorting TPAG to ground will bring Power Supply voltages back and 3 horizontal lines will be displayed on screen. I changed c914 as in the tips section and no change. I believe it may be in the vertical section, but not familiar with this chassis. |
| Vertical output device and associated electrolytic capacitors. Also may be a defect in the supply to the vertical circuits. |
| QUESTION NO. P725-4: Zenith pvr4663rk projection TV has a color shift. At the convergence adjust screen there are red vertical adjust lines instead of white. Replaced deflection board three months ago because of no video. |
| Check for fractured solder joints to the main convergence components. Use a 10X magnifying glass to check. DO NOT TOUCH the convergence controls until you have checked, tested and rechecked or found and replace bad components. It is a bear to get back to the factory sets on the convergence pots. Also, replacing convergence modules on some models that have them, truly fixes these types of problems. |
| QUESTION NO. P67-3: Hitachi 50ex20 projection TV AP 52 chassis, the on screen menu keeps appearing automatically. After a little while the set starts to cycle between video1 video2 and tuner repeatedly. |
| I have seen the yellow glue on the circuit board at the microprocessor become conductive-scrape it all off! |
| QUESTION NO. P523-9: Six sets of NEC GP-3000 Projectors. When I put power to them and a video signal, the set will not activate. A standby signal blinks. Is there a procedure that I need to follow to activate the projector? |
| There are dipswitches on the back panel of the unit, and they are currently set to work with a remote switcher unit. Change the dipswitches to allow use in local mode. There should be a switch legend on the bottom of the projector. |
| QUESTION NO. P516-10: Pioneer SD-P5575 projection TV, the red convergence in the lower 30% of the screen has suddenly become off. It begins to arc up from the lower right to a peak of about 4" in the center of the screen and completes the arc about 1" high on the lower left of the screen. The result is a double image (in Red) in the lower third of the screen. The portion of the picture above this is perfectly aligned. When I put the unit in convergence adjustment mode, Red is properly aligned horizontally and appears to be shifted up vertically (cross test pattern) and is adjustable but makes no real effect on the display picture. (The horizontal marks are at the screen midpoint so may be of no value.) Pulled the back and cleaned up the dust (4+ years old). Did not observe any obvious connection or burnt component issues. |
| Find large STK on convergence panel under front speaker. Change it (STK-xxxx). Also check resistors for change in value. |
| QUESTION NO. P54-9: Sony krp-46ex20 projection TV has a convergence problem. The screen has red, blue and yellow shadowing. Tried to center picture and the r h and r v do not work. |
| resolder convergence ic's. if that does not work, change (STK-xxxx). |
| QUESTION NO. P58-5: Sony KP-53S15 projection TV. Initially after turning on "power," I can hear it trying to perform some type of P.O.S.T. but within 2 seconds, it does not power on at all. The "Standby/Timer" light on front panel will blink once or twice and then it shuts off by itself. cannot find any blown components especially on the power module. Could not fin a power protection switch. I can hear some type of relay trying to energize but cannot tell which one on the power module board. |
| Check convergence board for possible blown fuses. |
| QUESTION NO. P526-9: RCA P52151WK (CTC169) projection TV has good sound, OSD, menu, but no video or other raster. Red convergence is pulsating on OSD characters. |
| Fixed it myself. Removed solder bridge across C2712 to restore raster. Reterminate bad red HXV connection in divider block to eliminate red pulsating. |
| QUESTION NO. P526-3: Sony Kp-61V15 projection TV. In Picture-in-Picture mode only, the color is not Synchronized (color bars rolling through). When swapping from PIP to main screen there is no color lock issue. So only the PIPtuner is involved. The color is Unlocked in PIP mode no matter which input source is selected (Antenna, video 1, 2,or 3). |
| Since it affects the PIP when bypassing the PIP tuner than it obviously is not the tuner causing the lack of color sync. I would suspect something on the PIP sub assembly or bad smd caps. Specific to the pip circuit only after the tuner and if section. |
| QUESTION NO. P424-10: RCA ctc195a projection TV has loss of signal when f connector moved. Acts like RCA ground or memory problem. Newer versions have aluminum chassis struts not steel like older models. Looked for broken connection and found none sooner or later f connection repairs coming. |
| remove both lower shields on tuner and solder ground connections. Also resolder IF shields. |
| QUESTION NO. P327-1: Sony KPR53CX35 projection TV has no picture, has sound. There is no high voltage. |
| Replace jungle IC. |
| QUESTION NO. P324-3: ptv 377-ah01 projection TV. Looking for front replacement screen part #646388-3. |
| Chassis number sounds like a product from North American Phillips. Try them in Greeneville, Tennessee. |
| QUESTION NO. P45-6: Problem with convergence board power supply on Zenith PV4651H projection TV. Transistor Q3401 was bad, unable to cross reference the number on it presumably a Zenith # which is 1086-3 in a TO-220 package. Have a service manual on order but will be a 2 to 3 week delay. |
| Put 121 prefix in front of transistors and check for cross reference. |
| QUESTION NO. P45-3: Hitachi cu4601b projection TV chassis a vp8x has no raster. Checked hi-volt, screen, 240 volt, filament, horizontal, vertical. All are present. |
| How about the convergence outputs and fuse devices, vertical output, leaky caps in protect circuit? |
| QUESTION NO. P410-10: RCA PTK169PTB projection TV blows HOT. Replaced fly, damper diode, pin damper, C4401, C4402. Went to RCA service procedure for hor deflection problems. While monitoring hor waveform, the Q4401 base OK till line voltage increased to approx 50 to 60 vac. Then bad drive destroys hot. |
| One of your deflection yokes is shorting when the HV reaches the proper voltage, which can be very fast. Try checking each horz winding of the yokes for leakage. It may not show up on a leakage test. If you can unplug each yoke, you can locate it, but this means blowing the trasistor, untill you get the right one. |
| QUESTION NO. P412-7: Mitsubishi VS-4003R projection TV only turns on sometimes. Stays on for random amounts of time (1min-5hours), then clicks off. If I try to turn back on, just clicks. Usually before it dies you will get vertical jitter and sometimes total vertical picture compression. Installed circuit modification kit, no difference. |
| You have bad solder joints on the circuit board. Check the horz driver transformer, solder these connections. Resolder the connections on the vertical IC. Resolder the connections in the main power supply. |
| QUESTION NO. P314-4: Mitsubishi VS-457R projection TV. Red convergence jumps way out of whack, horizontally, after the set has been on for a few minutes. Then, it wiggles back and forth. After 15 minutes or so, it locks back in and stays good for hours. It is not dirty contacts in the user's convergence pots. This set has a horizontal speaker grill, below the screen. The chassis is just behind this grill. This grill is removable, allowing easy, front side access to the chassis. |
| The problem is most likely the STKxxxx convergence output ic's. There are two, one for red and one for blue. Change them both, the blue one will also be going soon. They are not expensive. |
| QUESTION NO. P228-9: Toshiba TP48C50 projection TV has convergence problem. The vertical red line all the way on the left side is couple of inches off. While turning the internal cross-hatch pattern the vertical red line looks like bow. I was thinking about replacing the whole convergence board. |
| Replace the STK-392-xxx output ics, also check the fuse devices on the convergence pcb. Fixes about 98% of these sets. Should have STK-392-020 ics in that ckt. |
| QUESTION NO. P216-7: Pioneer sd-p5107 projection TV when turned on it takes approx. 5 mins for picture to show and another 5 mins for the picture to stop blinking before it is stable. |
| Check for multiple poor solder connection on the sweep/power supply board. |
| QUESTION NO. P217-10: Mitsubishi vs6087 projection TV with vertical jitter. Twice in the past 6 months the tv has been serviced after the installation of a vertical jitter kit v14vj. The basic curcuit is not stable and the kit has not solved the stability problem. |
| Check if the set has the small plugin pip pcb. If it does change C-7001 on the pcb and check for damage to the traces from the electrolyte from that smd cap. |
| QUESTION NO. P214-8: Mitsubishi VS4507R projection TV clicks when the remote turns it on. Looks like capacitor C909 was leaking. Will this cause this error? |
| Inferred that the set goes into shutdown? Check for overload in supplies, esp to the audio and deflection ckts, especially the vertical. |
| QUESTION NO. P120-8: I have the same question as question number P1115-8 PT-51G50U projection TV comes on normal and shuts down in a couple minutes. Have to unplug and push power, then comes on and shuts down. The Projection TV I am working on is a Pioneer SD-P5062Q and I have not replaced any capacitors. Should I replace the capacitors? Is there a Mod Kit for the Pioneer as there is for the Panasonic? |
| Many poor solder connections on sweep/power supply board, Probable bad electrolytics and leaky diodes on same pcb. |
| QUESTION NO. P125-5: PTV711-AH01 projection TV, red raster lines are distorted. Optical focus procedure followed without success. It is possible the distortion was caused by a magnetic field, is there an internal degaussing procedure? Another possible cause is failed focusing circuit. |
| HV, Focus Block, CRT drive pcb, CRT, Fluid, Dynamic correction circuits. |
| QUESTION NO. P110-2: Magnavox 52" RJ8550 AK03 projection TV is dead. Main fuse blows. Checked Horizontal Output Transistor and is shorted. |
| If Q10 on power supply board is shorted, then Q10 on deflection board is shorted. |
| QUESTION NO. P112-4: RCA PPR400P Projection TV both 1.5 amp fuses (F903 & F904) on the VP6X Power Sub PWB board blow when the set is powered on. I disconnected all harnessess to/from this board, and one by one reconnected until the fuses blew. The offending wire harness was connector GB. I tried to ohm D1455, Horizontal Output but this device has a dampening diode. |
| That set was made by Hitachi. I have seen this problem dozens of times, every time it was only a shorted horizontal output transistor, Q702 I think. |
| Contact RCA, there is a mod kit for repeated hopt failure. |
| QUESTION NO. P24-6: Mitsubishi ts-4553 projection TV, the red started to seperate in the right top corner. Now it is spreading to the outer edges of the hole screan. The center of the screen is still in focas. Also how do I align the colors using the remote? |
| Sounds like the classic cracked solder joints. If the color is spreading out over the screen you do not want to touch the convergence controls just yet. Pull the convergence board and using a strong magnifier, look very close at all the solder joints, especially on the Modules. I have fixed many of these problems just by re-soldering cracked solder joints. If the convergence was "in and good" before it started having this problem then this should bring it back to normal. However,if you play with the convergence controls prior to re-soldering then get ready to do some serious alignment time just to get it back to the way it had been before. |
| Change the red convergence STK and you will not need to adjust the convergence. |
| QUESTION NO. P114-3: Barco data 600 3 tube proj TV. I have to change the blue and green tubes. The original tubes are Sony SD-187, but I can find only the new Sony 07MS, do you know if this tube can work on the data 600? (it should use a higher focus tension). Perhaps it is possible to find the original tube direcly from Sony but I do not have the part #. |
| The SD 187 numbers from an authorized Sony parts distributor like Andrews Electronics or Standard Electronics will be enough for them to look up the correct #`s. I hope you understand what a major task it is to replace and then converge this unit after you have disturbed the tubes. Good luck if you do not have the service manuals! |
| QUESTION NO. P120-7: RCActc169 project TV has two problems. Arcing at anode on blue tube. Has made hole on anode plug. Oily substance leaking from anode. Also, lost remote control, intermittent control with buttons on front of set, intermittent turning on set. Eeprom? |
| You will have to replace the anode lead and the sealant at the blue tube & it`s a real pain. As for the interm. start I would say HV divider block not e-prom. Try removing the anode lead that comes from the flyback transformer out of the divider and rest it inside a coffee cup or other suitable non conducting container. Now start up the set, if it stays running then the HV divider block is bad. |
| QUESTION NO. P119-6: RCA ctc176 chassis on projector TV starts up but shuts off. Repeats three times and locks. Customer connected ouput of home receiver to speaker ouput of TV. Checked audio section for dead short across b+ to no avail. |
| Try disconnecting the anode lead from the HV divider block and then start up the set ( I put the anode lead in a coffee cup so it won`t arc ) if the set now starts up and stays running you need a new HV divider block, fairly common with RCA proj. units. |
| QUESTION NO. P21-10: Sony Videoscope XBR KP-53XBR35 projection TV had a blue convergence and pincushion problem. I found that the convergence chip IC1705 had a cold solder joint and resoldered it. The set worked fine for a couple of days then F902 blew. I replaced the fuse and it started working prefectly again. A couple of days later the TV powered itself off and stayed off. The power relay clicks once a couple of seconds after plugging the set in, but there is no response when trying to turn it on. |
| You need to replace both Ic`s, 1704 & 1705, check both fuses and the low ohm resistors to the convergence circuit. very common problem with those Sony`s. |
| I replaced both STK's and found two burnt out percision resistors and one blown fuse. It still does not power up. The 18V power supply is measuring 0.4V. Are there any conditions which have to be met before the 18V turns on, or is it a bad supply? |
| The set will not power up because the +18v and/or the -18v power supplies are bad. These are located on the power supply board (G). This board is no longer available from Sony. For the +18v supply, check the half-wave rectfier D604 (D10SC6M). For the -18v supply, check half-wave rectifier D605 (D10SC6MR). Also check R604 for continuity. It is a combination .1 ohm, 1/2 watt resistor and fuse in one package. |
| QUESTION NO. P110-7: Mitsubishi VS 4502R projection TV will not turn on, power relay clicks but set does nothing. Shorted TPAG to ground to override relay control. Get three horizontal lines, red line has slight bend about 30% from left, other lines appear straight. |
| Most of these type sets have a capacitor C914 which is open or close to open that causes the set not to turn on. I fixed two sets with different model numbers with this capacitor changeout. |
| QUESTION NO. P1213-1: Sony KPR 4110 projection TV has no picture but sound. Has graphics. |
| Open icps on convergence board. After changing check to see if conv. out ics are getting warm. If not, it is a bad ic. |
| QUESTION NO. P1223-8: RCA P46732BA projection TV will not power up. Found horiz ouput shorted Pn 2SD1885. Replaced, tried to power up without high voltage wire connected to HV SPLITTER. Power up okay with sound, replug HV wire to SPLITTER, blew horiz output again. Is HV SPLITTER BOX bad? If so, where can it be found? |
| Yes, block defective, special order thru RCA distribrutor. Confirm proper part number of device, more than one that looks similar! |
| You will have to replace the HV Divider Network, and now the HOT, again. Removing the anode lead and powering up the unit is the check for this set. If the set is a CTC169 chassis the part # is 205064. Replace the divider and the transistor at the same time. |
| QUESTION NO. P1117-9: Magnavox RK8568AK02 rear projection TV. Picture green and foggy. Drained, cleaned lens and replaced. Picture fine. Having trouble diagnosing second problem. When powered up, unit will take from 5 - 30 minutes to "warm up". During this time, no picture but has sound. Intermittent flashes from gun can be seen on screen in short, narrow band on far left. Small band converges eventually into white dot, and then the picture expands to fill the screen. Picture and unit operate fine until shutdown. If turned off and then back on, set resumes "warm up" routine as described above. |
| Never seen unit, but symptoms sound like bad caps. Check voltages on power supply board and check all electrolytic caps. Also check out convergance board, may be a regulator on it's way out. |
| Here is a tip on your delayed warm-up issue. Get a good magnifying glass and check the solder joints on the power supply board beneath the flyback xformer for cracks (or just resolder them for spite!). If these are cracked then the flyback will not fire off until thermal expansion in the pc board forces a connection, which can take up to several hours after set is turned "on". |
| Replace C450 & C455 filter caps on the 13v line on the signal board. Both are 470uf at 25v. |
| QUESTION NO. P1124-5: RCA p46770ck chassis#ptk169paas projection TV keeps taking out the h.o. It was shorted on first check. Replaced, blew it right away. Replaced c401k and the flyback. Still takes out h.o. Have checked all diodes and caps in both lv and hv pwr supplies. Also checked the yokes res. wise and they seem to be ok. I do have the sm for the unit. |
| PCC diode and cap, located directly in front of the hot transistor. Also yoke return caps, blue in colour, change any that are slightly swelled. |
| Change the following all at the same time: C4401, C4402, CR4401, CR4402. |
| Possibly a bad/shorted Hv block. Since it's taking out the HOT you have to think that the draw on the HOT is further down line and after the flyback. |
| QUESTION NO. P1123-5: Sony kp-46v25 projection tv. Blown 601 fuse on D board. Disconnected red convergence plug from D board and replaced fuse. TV will work in this mode but red convergence is not working. If I disconnect blue convergence plug and connect red convergence wire, the red convergence can be adjusted using the blue on screen convergence controls. If I plug the red convergence plug back into its correct location the fuse will blow. I suspect one of the ICs (1601 or 1602) is bad on the D board. With the red plug disconnect. |
| Replace both STK output ics and associated fuse devices. |
| QUESTION NO. P1026-2: Panasonic PT-L592 projection TV. I need a source for the Mine-Board serial number TNPA 0665AC. |
| Panasonic only, will probably require special authorization. |
| QUESTION NO. P1027-10: Older Sony projector, model number is scratched off, but starts with vph, date on side is 1985. Uses sd-130 tubes, delta ii-d optics. Where can I find replacement optics & how does this projector switch projection? |
| VPH-1000M info should suffice. |
| QUESTION NO. P1027-5: Pioneer SD-P505 projection TV. Looking for a source for projection CRT's of Hitachi # 180BSB22 tubes. |
| Pioneer can supply original crts or a rebuilder can repair the originals if they havent been damaged. |
| QUESTION NO. P1122-7: Hitachi 50UX23K projection TV has dark smeared shadow areas on the screen. They cannot be removed by cleaning the outside or inside of the screen and appear to be caused by either a substance between the Lenticular and Fresnel lenses or a discoloration of the lens material. |
| Seen materials stain the screens that is very difficult to remove without causing damage. Some of this seems to migrate between the screen assemblies, usually from the bottom or lower corners, seems to happen a lot if there is a high amount of air contiminates present, be it smoke, dust, etc. Only answer we have found that works is a new screen. |
| The screen can be cleaned with a rubber-type pet hair removal pad, the untreated kind. Don't have a brand name for the pad, it is cream colored and looks like a sponge, used to remove pet hair from clothing and furniture. |
| QUESTION NO. P1115-4: Zenith PV4543P projection TV. I need a source for a red picture tube, E.I.A=A13ABRORF, Zenith=100-749, Equivalent=A-12809-02. |
| Any Zenith parts distributor should be able to supply the component. Other than that try crt rebuilders, if the original still retains it's vacuum and coolant. |
| QUESTION NO. P1116-8: Magnavox rf8505ak06 projection TV, when powered on there is a momentary HV charging and then it quits with a mild audio thump. The LCD tuner stays active but nothing else. |
| Power supply or sweep module. Check the crts for contaminated coolant fluid and excessive wear. |
| QUESTION NO. P1116-5: Mitsubishi VS-485R projection TV. Found shorted hot and replaced. B+ voltage reads 135V, manual says it should be 170. Tried isolating all board outputs to look for short (including yokes) could not find any. Cannot tell if there is something dragging voltage down or if there is a power supply problem. |
| B+135 is normal, possible the print has been mis-labeled?? Suspect something other than your supply. |
| QUESTION NO. P1115-8: PT-51G50U projection TV comes on normal and shuts down in a couple minutes. Have to unplug and push power, then comes on and shuts down. Replaced several capacitors that were leaky did not fix problem. |
| Needs mod kit from Panasonic. You must recalibrate hv shut down. This is very critical! |
| QUESTION NO. P119-3: Mitsubishi VS-70601 projection TV with no control over the blue convergence. Blue vertical & blue horizontal have no effect. Red & green converge OK. |
| Convergence output devices [ 3 ] change them, inspect both + - supplies to convergence ciruiit. Check for open fuse devices. |
| QUESTION NO. P119-2: Hitatchi 60SX2K Projection TV. In convergence set up screen, lower left corner shows severe distortion horizontally with angled convergence on all corners. Moderate distortion vertically. All three guns involved. Good color. Slight changes with temperature or prolonged use (ie 2 or more hours). No visible loose connections, unit cleaned and inspected, no foreign material found. |
| Complete full digital convergence on this set then operate for an extended peroid of time, over 3 hrs. Check convergence again, if it changes, suspect the output devices and supplies. Very rarely the dac may be affected. |
| QUESTION NO. P1110-10: Pioneer SD-P4691K projection TV. Degaussing relay cycles about three times. Unit is dead. 135volt B+ is low. |
| Sugggest checking the sweep/power supply panel for numerous poor solder connections. Check the convergence output circuits and hv sections sepcifically. These sets seem to develop a fair number of ring cracks at component leads thru the pwbs. |
| QUESTION NO. P1013-3: Mitsubishi VS6017R projection TV takes several tries to get it to stay on. Often the picture is in black and white for the first several seconds, then every runs fine. Problem is too intermittent to troubleshoot. |
| Change C914 (22uf, 50V). |
| Toshiba RPTV Model # TZ50V61/71. I have seen 3 of these sets that have sustained shipping damage. The mounts for the crt support are held in with red glue and staples, they fail during transport. The crt assemblies then fall onth the chassis assemblies below smashing wither the crts, chassis boarda, and/or both. Visual inspection from the outside is not evident of problems, must remove rear apron to visually inspect for damages. |
| QUESTION NO. P1025-2: Sony kp53xbr35 projection TV. Convergence IC's (2 x STK4278L) replaced in June 1999 along with fuses. -18 and +18 volt supply appeared OK. Worked for a couple of months, now same problem. I received a reply in sci.electronic.repair that said the pins on the IC's have to be bent a certain way or the IC's will burn out again eventually. Does that make any sense? Both times the problem occurred was when the set was first turned on not after it had been in operation for awhile. I have service manual. |
| Be sure and apply heat sink compound to the back of the STK's. This will help, but it won't eliminate what is obviously the weak point in that set's design. The Stk4278L has the L on the end to denote the L bend in the pins, using a Stk4278 would necessitate bending the pins. I can't see how that would be a problem, if done with care. |
| QUESTION NO. P1022-8: Are there any tips for repairing scratches on projection television screens? |
| Yup, it is called ordering a new screen. Most of the remedies I have seen/tried do not result in a clean repair and usually do more damage to the screen. |
| I recoverd mine on a front projection sony with a movie projector screen. You lose a little color but it is better than scratches. |
| QUESTION NO. P927-9: Sony VPH-1031q projection TV will not power the fans and gives a solid vertical line for a few seconds before shutting down. |
| Loss of vetical sweep and protect. Check the vertical output and supplies. |
| QUESTION NO. P107-7: Magnavox RH8520 Ak07 projection TV has no picture. It has a horizontal bar about 2 inches high across the center of the screen. It is predominantly blue. The "on/off" switch will turn the TV "on" but not "off". It has to be unplugged to turn "off". There is no audio. The two IC's on the Horizontal Oscillator Board are an SN94366n and a KY8630. I suspect one or both of these may be defective. Where can I get these two IC's? |
| Phillips/Magnavox Greenville Tennessee. BTW, how is the fluid? Congealed yet? |
| QUESTION NO. P1018-5: JC Penney projection TV ctc132d ch. After 20min. crts go out. Blue still slightly dim but intermittent. All solder coonnections good. |
| The RCA/Hitachi designed CTC132 has a zero balance adjustment on the pcb just to the left when the front apron is opened for service. The adjustment is made between tp1 and tp2 for as close to 0 volts offset as possible. If this voltage can not be attained there may be problems in the convergence and/or vertical deflection ckts. As old as this set is the electrolytica in any of the ps and deflection ckts may cause problems; also check the auality of the crts. |
| QUESTION NO. P106-6: Mitsubishi VS405R projection tv. All fuses are okay, but IC Proctector Z901 was open. I changed it now and I get sound but no picture. The number display is on. Vertical circuit and H-output is okay. The guns are not on. |
| One of the yokes may be defective. Common problem with these older MGA sets. |
| QUESTION NO. P924-9: Mitsubishi 46" VS466-rs projection TV has sound but no picture. All voltages seem to be there. I can hear the static of high voltage when turn it on and off. There were a couple of resistors on the B+ line got hot and burnt the pads. I repaired them. The filaments voltage is there, but they are lit up. |
| Check vertical deflection and yokes. If HV is present, truning the G2 up should show some type of display, be it flat trace on screen or a blank raster?/ Also check convergence ckts. |
| QUESTION NO. P930-5: Zenith pv4545p projection TV. There was a slight arcing in the red tube the set turned off. When restarted came back on twice then kicked off again. When turned back on had sound but no picture. |
| Check the HV/Focus assembly. Also for problems now on the deflection pwb. |
| QUESTION NO. P929-2: Mitsubishi VS-5007R projection TV has no vertical deflection. Replaced Vert-output IC and caps in that circuit, but still no vertical defection. |
| Check R540, a 1 ohm resistor off the flyback. |
| Check the supplies to the vertical ckt. Derived from the FBT, etc. Also check connections to/from yokes. |
| QUESTION NO. P928-9: Is it possible and/or easy to replace crt coolant on Sony 46" projection TV? Coolant available from Sony or a standard part from a supply house? |
| MCM can supply the fluid, changing it requires removal of the old fluid with a turkey baster or similiar device. Then use long length cotton swabs to clean the residue from faces of the crts. Use of alcohol or other agents applicatable but make sure all of the material is removed from the cooland chambers before refilling. Time consuming but worth while if the crts are not fried. |
| QUESTION NO. P929-7: Zenith PV4657LK Projection TV has lost its picture.When the the power button is pressed, the HV comes up and the red gun fires for just an instant,the green and blue guns fire for about 20sec and then shuts down. There is a hissing sound coming from the FLB transformer. Could this be the problem or is it the related components? |
| HV/focus block? One of the crts gassy? |
| QUESTION NO. P930-10: NEC DP-5200s projection TV. I need an NEC part# 48009036 deflection yoke for the blue gun. The coolant from the tube leaked down into the yoke. Is it possible to "clean" or repair the yoke to acheive full deflection again? |
| Negative, where else did the fluid go? All over the deflection and/or signal pcbs? Are the tubes wasted as in most NEC proj? |
| QUESTION NO. P930-9: Zenith PVY5270 projection TV. There is no service panel in the set to adjust the convergence on this projection set. The standard service mode (menu,9,8,7,6,enter) does not contain settings for convergence. What is the code to to enter the convergence service menu? |
| Try 999. |
| QUESTION NO. P930-2: Mitsubishi VS-458RS Projection TV. Z901 open, also found horizontal output transister shorted. Replaced both of these. Horizontal output transister got real hot so I replaced the Flyback, same thing happens. H V transister gets very hot. Replaced High voltage block, same thing. Tried TV with Flyback disconnected from H.V Block, Horizontal Output Transister still gets hot. |
| Check the yokes and return ckts. |
| QUESTION NO. P917-3: Magnavox - RJ8540 Projection TV. Problem was R2 R4 @ R6 blown on convergence power panel. Replaced and worked fine for about 2 months then it started to shut down after an hour on. The rest of the components seemed fine on the convergence power panel. |
| There is a short on the Signal/Deflection panel. Find the short before replacing 1 ohm resistors. |
| QUESTION NO. P917-1: Mitsubishi VS-414RS Projection TV. Need manufacturers name and part number for Capacitor C522. It is difficult to read but I believe that it is a 0.1uF cap rated at 1600V. Set has no sound , no raster, fuses good and B+ is OK. If I hit this cap with cold spray set will operate fine for a minute or so and then go into shutdown. |
| If you know the value of the cap, why would you want to order it from Mitsubishi? |
| QUESTION NO. P921-5: Sony KP-61V15 projection TV had a pincushion and focus problem. Replacing STK's and fuses corrected the pincushion problem. Unit still has very very poor focus. Lenses do not appear to be dirty (I did clean them) and the focus control does change the focus but never gets near to correct. |
| Try moving yokes slightly forward or backwards, then retry focus controls. Experiment, it often works. |
| QUESTION NO. P923-1: Memorex 44in projection TV at least 10 years old. Unit is missing rear panel, any ideas on a model #? Audio works, has no video. No Hv no filiment voltage. No blown fuses and boards are not burnt. I tested voltages on Main video board and it seems to have no voltage on the board. PCB has no blown fuses and the two transformers, do not seem to be shorted. The unit does not shut off it has audio when there is an input. |
| That is probably a Mitsubishi VS405. Common problem is bad yokes, but you would not have sound. You said no HV, but did not say if Horizontal Output transistor was shorted. If it is then either the 1.6A resistor will be open, or a protector IC will be open Z901 I think. Should be simple. |
| QUESTION NO. P924-7: I need flyback transformer p/n 2432422 for a 1982 RCA 45" projection TV. |
| RCA part numbers have 6 not 7 digits. The flyback probably isn't available any longer. If you had included a model # I could tell you. RCA wants about $150 for flybacks around that vintage. Are you sure 17 year old CRTs are going to look good enough to warrant the bill you will have to charge? |
| QUESTION NO. P923-2: RCA ctc169PA 52" projection TV model p52770eb. Will not power up. Orig fried R721u. Replaced and now have nothing except if hold power down have arcing. Removed anode lead from flyback to HV spliter and got power but again R721U fried. HV splitter bad? |
| Yes, the hv-splitter is bad. This part has high failure. |
| Follow-up: The HV splitter fixed the problem. Replaced the splitter and r721u. |
| QUESTION NO. P922-9: Need to know how to get into service menu to adjust convergence on a Sony Videoscope Rear Projection TV. (48" Model - Less than 2 yrs old. Hard to get at back to see model#). |
| On most newer Sony TV's, using the remote with set OFF Push DISPLAY-(5)-VOLLUME UP-POWER. That should get you in (be Very Careful). |
| QUESTION NO. P816-8: I need a blue CRT for a Quasar SR4000FK projection TV. |
| MECA parts should still be able to supply that part. If not, there are good rebuilders if the old crt is still intact. |
| QUESTION NO. P98-1: Sony vph1020Q projection TV. When trying to power on it goes on, off, on, off, it will not stay on. It seems to have some kind of power supply problem. |
| OVP. May be shutting the unit down because it sensed abnormal parametres. May be regulator or leaky caps in supply. Try powering up @ reduced input voltage, may help further diagnose problem. |
| QUESTION NO. P98-1: Sony vph1020Q projection TV. When trying to power on it goes on, off, on, off, it will not stay on. It seems to have some kind of power supply problem. |
| OVP. May be shutting the unit down because it sensed abnormal parametres. May be regulator or leaky caps in supply. Try powering up @ reduced input voltage, may help further diagnose problem. |
| QUESTION NO. P915-6: Ampro HD-3600 projection TV. Ampro has gone out of business leaving questions on where to source repairs. The common CRT seems to be a Thomson 9262.00. We will be having this problem since Ampro is no longer answering phones. |
| Check the FCC database for original manufacturer and try contacting them for parts. Good Luck. NEC did effectively the same thing with their Consumer Products. |
| Elite Video (781-938-6606) repairs and sells parts for Ampro Projectors. They even sell some Ampro models. |
| QUESTION NO. P915-6: Ampro HD-3600 projection TV. Ampro has gone out of business leaving questions on where to source repairs. The common CRT seems to be a Thomson 9262.00. We will be having this problem since Ampro is no longer answering phones. |
| Check the FCC database for original manufacturer and try contacting them for parts. Good Luck. NEC did effectively the same thing with their Consumer Products. |
| QUESTION NO. P915-7: KP-53v15 projection TV has sound but no picture. It only has two arched red lines about 1/3 down from the top of the screen. |
| Check the fuses on the convergence output pwb. If either one is open replace the STK output devices. Also, check for any ring or service cracks in the soldering of the other components on this pwb. |
| QUESTION NO. P99-4: Mitsubishi VS405R projection TV. I am trying to locate an HV block Part Number 920P00501 (MURATA MSC05-02A). I have been told it has been discontinued. |
| Check with David Gibson @ 1-800-400-6386. Detroit Michigan area. |
| Try CRC Components 1-800-822-1272. |
| Try a company like Electronix 1.800.223.3205. Are you sure that is the problem? They normaly have bad yokes and horiz out. Yokes are now available through subarban, so are some of the fbt. |
| QUESTION NO. P813-7: Hitachi ct4532 projection TV which has a very ghost-like picture . It appears to be almost like a negative image. I am unable to adjust brightness tint or any picture functions yet convergence seems to be adjustable. I tried to find a replacement pc board for the whole main chassis but have not found one yet. |
| That Hitachi was manufactured from '82-'86 so it is between 13 and 17 years old. The bad picture is probably just worn out picture tubes. The main boards were never available, that set was designed to repair to component level, not board level. The only thing I would try is cleaning the mirrors,(that set had two) and removing the 3 tube assembly and cleaning the faces of the picture tubes and lens. |
| QUESTION NO. P97-8: Hitachi cT4532 projection TV. Looking for a reliable parts supplier for this unit. Any info on correcting alignment issues? Also looking for a low-cost method to restore belzier lens. Appears to have crayon marks on it. |
| Look for many dry electrolytic caps and ring cracks in the convergence waveorm and output circuits. Hitachi, I believe, no longer supplies specific components for this model due to it's age. Crayon on the Lenticular screen can pose a major problem since any cleaner that will remove the crayons; or hot water; applied may also remove the paint between the ridges of the screen. |
| QUESTION NO. P817-5: CTC169pa rear projection TV . The sets supplies are running ok in standby but as soon as power on is pressed the supplies drop back. No high voltage is gererated at all. I have checked for secondary loads also high voltage caps, even convergence supplies. Customer noted a flash before set went down. I am suspecting bad tube or high voltage block. |
| Problem could very well be the high voltage splitter block. Unplug the high voltage wire from it, if set turns on, you have isolated the problem. Unfortuately the part is on national back order, word is RCA is remanufacturing them. Get your order in now. |
| QUESTION NO. P715-4: Fisher PT800 40" projection TV serial # is V5400900233 with Q707 and Q708 missing on the power supply. |
| That Fisher is about 15 years old. Many parts are no longer available. If you can fix it, the picture tubes will surely be very dim, and the grey scale will be virtually without green. Don't bother fixing it. |
| QUESTION NO. P715-5: Sony VPH600QM projection TV. Just replaced from Sony 1040 CRT(suggested). Everything ok except when screen all white sky are white then all the pixels or image gone foge fuzzy, focus problem reduce bright and pic ok but picture not bright enough. Reduce video gain does not help. Is it just the way CRT works nothing I can do about? On the test pattern I can see the blue gun is more fat then other and that is best focus I can get. |
| It sounds like the projector you got has tired tubes. The controls are turned up to compensate but when the screen goes all white the adjustments cannot keep up. As for the blue being "fatter" this is standard. Every Sony VPH I has used requires the blue to be slightly out of focus for the right brightness. |
| QUESTION NO. P628-7: Pioneer SD-P5053 projection TV. Getting horizontal "noise" lines randomly throughout picture. Is there a service mode? How do you access it? |
| Horiz. noise lines can be caused fy electrical interference, RF interference, or a multiple of other things. If you are asking about lines in the pix that also seem to tear the pix or interfere with the sync [ vert jump] that could be a signal processing or even a signal problem. There is a service code available for adjusting these sets but probably will be of no assistance unless you specifically have a convergence problem, have changed the output devices, and need to reset the geometry. |
| QUESTION NO. P77-5: Magnavox 46" RH8530 46" projection TV, (had a faulty flyback, but got replacement power board) now I have a few minor problems. The blue color doesn't want to focus; I get a blue haze around any white surface, peoples eyes look like freemen from Dune. I have tried adjust focus knobs, and brightness, etc. (all readily labeled adjustments). Contrast is too drastic. Again tried adjusting everything labeled. When I supply a video signal into the auxillary, the screen jitters vertically (maybe a couple inches). When the signal is removed, a on screen display menu only jitters slightly (less than half an inch). |
| As far as the blue haze and focus goes, look into the blue lens assy. If the coolant is cloudy or has debris floating in it, the coolant will have to be changed and the lenses and crt face will need to be cleaned. Coolant can be ordered from any electronic distributer. I get it from MCM. |
| I had the same problem with a Mag 52"not being able to focus one of the tubes. First thing to check is the high voltage splitter. Look inside from the back for a black box with 6 small knobs, 3 control focus and the other 3 control brightness. It is best to have a color pattern generator to make sure these are even but a good eye is just as good. Also check the actual lens for dust. If not dusty, look into the lens while the set is on. This will be bright so do not look for too long. Magnavox uses collant liquid that breaks down faster than other PTV's that I have worked on. If your blue looks cloudy inside and the others are clear you may have to change the fluid inside. An air bubble in the lens will cause a hazy tube also. |
| Regarding your "jitters" under video input, try removing the jumper from the vcr mode switch jack (named "vert") on the horizontal oscillator board. That will default the horizontal to "standard" frequencies instead of non-standard (sub-standard??). |
| QUESTION NO. P618-4: KP46S55 projection TV. The picture intermittently narrows, with pincussion distortion. I changed the convergence Stk's. |
| Check the pin output transistor and associated capacitors. Usually the area around the transistor is discolored from excessive heating of the transistor. Also check the other active components in the pin ckts. |
| QUESTION NO. P611-7: Pulsar VPM-2000 projector thta has the same electronics as Zenith PV-800 series. The remote control and the keyboard panel did not function after some minutes of turning on the equipment. I found out IC-6200, part#221-366 defective but I have some difficulty finding a substitute. |
| That is a good Zenith part number and should still be available from a Zenith distributor. |
| QUESTION NO. P69-10: Sony VPH-1272Q Front Projector. Need to know how to enter the Service Menu to adjust edge convergence/alignment. |
| You enter the service mode by holding down the "Test" button for about ten seconds, at which time you will be prompted on the screen to press the up arrow to enter service mode, and then finally you will need to press "Test" again. This allows you do adjust the fine convergence and all the geometry, as well as the bias and gain of the 3 guns. The Electonic focus and "Screen" controls are under the case in a black plastic grouping to the right of the keypad. |
| You need to hold down the test button for about 5-10 seconds. The projector will ask you if you want to enter the service main menu or something like that. I hope you have the service manual handy or experience in doing convergence setup. Because if you lack experience in this area you can get yourself in a lot of trouble and get the projector all out of whack. |
| QUESTION NO. P524-10: NEC GP3000 Data projector. Looking for CRTs (red, green, blue) for an NEC GP-3000 data projector. NEC no longer manufactures these CRTs and is "out of stock". |
| Suggest contacting a rebuilder and getting a quote for refurbishing the original crts. That is if they have no scratches on fluid leakage. NEC has been getting real bad about supplying parts for older units. |
| QUESTION NO. P62-7: Seleco SVT-190 Projection TV. There is bad green CRT. It uses the Sony 07ms(G) tube. Sony parts cannot cross that number to the standard X-XXX-XXX-XX type of part number. Does anyone know the Sony part # for their 7" color CRT's, OMS series? |
| You may try referencing the part numbers printed on the tags attached to the original crts. Contact a rebuilder for a quote on refurbishing the original crts or they may be able to cross them to the required Sony replacements. Tele-Video is one source for rebuilt direct and proj crts. This may be an option. Check for a local rebuilder, ask service facilities in your area who they rely on for this type of product. |
| The part number listed for the 07MS (G) are 7-012-401-50 or 7-012-301-56. |
| QUESTION NO. P64-4: RCA PMR 500T Projection TV. The High voltage box is damaged and need to be replaced. Thomson Electronics is saying that the part is obsolete. The part number is 173494. |
| Like getting dash gauges for a Henry J automobile. If you can find a company that has one they parted out would be your only viable source. Good Luck. BTW how are the crts? Hopefully you have checked them before going to all this trouble? |
| QUESTION NO. P62-9: Mitsubishi VS-5061 Projection TV. The red separates from the picture on the right hand side of the screen. No adjustments seem to remedy the problem. |
| Failure of the convergence output devices. Probably STK4273.74 series. |
| QUESTION NO. P62-6: Pioneer SD-P5053 projection tv, replaced HV transformer(leaking). Powered up and the flyback sounded like it was arcing. Replaced flyback and resoldered board to no avail. |
| Sounds as if it is time to order the complete sweep board from Pioneer! |
| QUESTION NO. P61-9: Where can I find procedures for adjusting color and convergence potentiometers for a Pioneer SD-501 projection TV? |
| Best place would be the service manuals from Pioneer. There are some very specific procedures that they only cover in the specific service manuals for their products. |
| QUESTION NO. P517-5: Electrohome ECP 4000 front projection TV. The problem is with the green CRT. It has a spot of brightness and fuzziness. At first I thought it was burn-in but that would make the spot dimmer brighter. I have a replacment tube I just want to make sure it will fix it first. |
| Try swapping the crt drive boarda from one of the other colors. If the symptom stays with the green then the problem is in the crt, if the problem shifts to the other color then it is ckt generated. |
| QUESTION NO. P518-4: KP-46V15 Sony Projection TV. I have a yellow vertical band on the right side of screen, after adjusting the convergence the white cross has a little yellow on each side of the horizonal cross. |
| Check the coolant fluid for bacteria growth. Fluid should be clear, not cloudy. The contimination tends to be worse on the blue and green crts but also affects the red. The material tends to difuse the light coming thru it and can cause a similar effect as de-focusing the lens. This may be exhibited as a display on screen that can be focused but appears larger than normal width wise. Similar problem as found in the Phillips proj tvs. |
| QUESTION NO. P512-5: Mitsubishi vs 648 projection TV. I need the main procesor chip (IC 701). Mitsubishi does not make it any more. The part # is 263p824010 or M50441-561BSP. Also is there a cross reference or other part # that would work? |
| Contact Gibson's Service @ 810-774-9730, ask for David. They have a fair supply of older MGA boards that may be available for a price. Fax line 810-774-5709 / 5485. Located in Greater Detroit area so shipping may also be a factor. |
| QUESTION NO. P512-6: Mitsubishi VS4501R projection TV, the power supply board is toast, to the point the traces are falling off the board. This board has been discontinued (1989 model), so I need to find a power supply board part # 935C278010. |
| Contact Gibson's Service @ 810-774-9730, ask for David. They have a fair supply of older MGA boards that may be available for a price. Fax line 810-774-5709 / 5485. Located in Greater Detroit area so shipping may also be a factor. |
| QUESTION NO. P419-9: Hitachi CU5000K proj TV. Tuner will no longer tune lower bands -- channels 2-48. Question number P817-2 stated similar problem. |
| Confirm the proper voltages to the tuner assembly. Try to resolder internal grounda inside the tuner. If voltages correct and ground repairs do not help spring for a new tuner. |
| QUESTION NO. P428-2: Nec projection 52'' TV. Need parts, also have weak and dark picture. May need tubes or power supply. |
| Many of the NEC parts for consumer products are no longer available. The crts for the proj tvs are rebuilt items only and are becoming rather rare. Are you really interested in investing $1400 to $1800 and getting used and/or rebuilt parts? If the set requires this extensive of repairs it would be economically more feasable to replace the set and use the old cabinet to house a fish tank? |
| QUESTION NO. P512-2: Mitsubishi VS-4571 Projection TV, has sound but no picture. The LA7838 had a pit blown in it. It has been replaced and now I have a picture, but it is just at the top half of the screen(the entire picture). The manual does not list the C-400 series of capacitors C402, C403, C411, C407, & C405. |
| Hopefully you have a good ESR Meter that you can use to check all the associated electrolytics. Also, I hope you did not cart blanche remove the capa and then toss them into a pile. Removing them one at a time and recording the value is consistant with effective trouble shooting procedures. Also sheck the resistors in the vertical and PCC circuits, A problem in the PCC can be exhibited as a symptom afecting the vertical and/or horizontal. The schematic to this chassis, and similar does list that series of components. You may need to find a master copy for that particular chassis. |
| QUESTION NO. P511-9: Sony VPH1270Q Projection TV, lost frequently its convergence after power off. |
| Check the convergence panel for possible solder cracks and for loose connections at the harness connectors. |
| QUESTION NO. P511-1: Sony KP-46V15 projection TV. When first turned on the picture is fine, after a 5 to 10 minute warmup the entire picture area will expand out most noticably in the corners causing a vertical line near the edges to look like it bends out at the corners. Also a convergence pattern will show the vertical center line to be as it should and the horizontal line shows a red shift to the right and a blue shift to the left. The picture will continue to pop into correct alignment and then again expand out at irregular intervals for the next 30 minitues to an hour when the picture will stabalized as a normal image. On a few occasions the overall picture will seem to darken slightly with a diffuse horizontal band of approximately 1/3 the heighth of the screen being more markedly dark. |
| Try the STK-XXXX convergence outputs and check the convergence panel for crackes solder connections. Also check the Pin output transistor and associated circuitry. |
| QUESTION NO. P429-3: 1986 Fisher 40" pt800a Projection TV. The manual controls will not adjust. Both the blue and the red will not move when adjustment is attemped. |
| 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. P323-6: Sony Rear Projection KPR-4110. Video muted, sound good, sleep light comes on for 10 seconds. Can unmute video by removing mute 1 line on convergence board but it will not let me adjust convergence for red or blue. All voltages tested were good. |
| You have a failure in the vertical circuit. |
| QUESTION NO. P322-1: Magnovox projection tv rj8555 low audio somewhat like the low volume problem on the rca ctc 175 chassic which has a bad eeprom . Both driver on audio power module have been replaced. |
| Check R-403, 404 (.2 ohm 1/2W) and R-401,402 (2.2 ohm 1/2 w) on the audio panel. |
| QUESTION NO. P319-6: KPR-4110 Rear projection TV (Sony). No convergence adjustment for red or blue, the ones using the STK4121II. Everything else ok. Green OK. I have checked all obvious (fuses, voltages, solder joints). |
| You did not say that you changed the stk devices, many times the prime suspect. |
| QUESTION NO. P323-9: Mitsubishi VS-583R rear projection tv. After about 10 minutes the red tube would lose convergence intermittently, then goes out of focus intermittently. Is there any service codes that can be entered from the controller? And do they still make parts? |
| No service codes and limited part availability. Suspect components on the convergence adjust/output panel, check for poor solder connections, bad electrolytic caps, etc. |
| QUESTION NO. P316-4: Zenith Pro891X projection TV has intermittent loss of brightness particularly on video with white background (hockey/skating). Brightness drops abruptly and then recovers. Problem difficult to troubleshoot because it is intermittent. |
| Inspect the HV/Focus assembly, if it is a one piece unit, having the G2 & Focus controls on the same assembly as the HV block change it. They have a way of forming minute cracks and causing intermittant shutdowns and other problems. |
| QUESTION NO. P225-8: Where can I obtain a service manual for a Philco projection television Model P8346B? |
| Philco is manufactured by Philips Consumer Electronics, Greenville, TV 800-526-9354 but you should be able to order it from any electronics supply co. that is authorized for Philips. |
| QUESTION NO. P216-8: Sony projection TV. Blurry picture without convergence problems. After removing lenses from the tubes, I notice a smudge-like appearance on the face plates of the CRT's. These coolant chambers appear to be factory sealed. How can I open up the chambers and replace the fluid, it also appears that the grime in the chamber will need to be scrubbed off. |
| What you will need. 1. New fluid 2. Denatured alchol 3. Some of those old fashion PIPE-CLEANERS, the long ones. (you can get them at a crafts store) What to do: If you were very carefull and did not disturb the yokes it should still be pretty close in alignment. |
| QUESTION NO. P216-4: Sony KP-53V15 rear projection TV. Sudden appearance of severe pincushion and color misalignment around the edges of the screen. The edges look like that are pulled in. Picture appears fine and aligned in the center of the screen. Reception and all colors are fine. The problem persisted since it appeared. Occasional flicker of the entire screen image. |
| Check the fuses on the convergence panel, also change the converergence output devices STK-XXXX, then check the board throughly for ring cracks ar the regulators and controls. Been finding a lot of these lately; also may have a pincuahion output problem but suggest trying the convergence fixes first. |
| QUESTION NO. P212-8: I need written material on how to change the fluid in the crt's. |
| MCM has some kits with instructions but basically you pull the crt and drain it. Remove the lense clean it and reinstall it without finger prints on the inside. Then refill it with new fluid. On Sony tubes, remove the plug & drain it. Then use a pipe cleaner with alchol through the little hole clean the gunk. Rinse and refill. |
| Varys with manufacturer and model refinements. Specific info available from manufacturer parts departments. |
| QUESTION NO. P121-2: Where can replacement fluid be obtained for a Magnavox projection tv? If possible I would like a quantity and not a one time kit. I was told if bacteria is present this problem will re-occur; thus the need arising again. |
| The fluid for Magnavox proj is availiable from any NAP parts dist (check Sams index for dist). It comes 4 bottles to a box, enought for all 3 tubes. I do not have the part #, but dist will know. Gaskets and O rings to crt fluid chamber should replaced also, so they will not leak. Disassemble the chamber and clean. Use denatured alcohol, or tap water, be sure to dry thoroughly before reassembly. |
| QUESTION NO. P29-3: Hitachi 46UX7B projection TV. Problem - Picture symptoms dark, red tint faces. Teeth or parts of teeth black or missing. Poor picture definition. Picture unclear and not sharp. Picture fuzzy. Ghostly picture. Red outline on edges of some white letters and numbers. White OK. Picture has somewhat appearance of a photo negative. Best picture (unacceptable) settings Contrast All the way up on bar. Color Approximately 1/3 way up bar. Brightnes almost all the way up on bar. Sharpness Little change from - to +. Tint Little change from - to +. to -. Tint little change from - to +. |
| Are the crts gone already? Rare but possible, however there have been a large number of these with problems in the PIP and COMB FILTER assemblies dealing with the surface mounted capacitors. They tend to leak the electrolyte onto the pcb & eat away the traces. Repair is to order the kits from Hitachi, remove the pcbs, and replace all the caps on each item. Check the quality of the crts and also the g2 supply voltages. |
| QUESTION NO. P23-7: Mitsubishi VS-50VF that has the picture shrink in on both sides when the contrast is run up or when a white screen comes on. There is a red line on the left and a blue line on the right. Also goes out of focus with a bright screen (white background in picture). |
| Trouble shoot the b+ circuit. Also check for a fluid leak from the red crt. |
| QUESTION NO. P127-1: Where can I buy three ic`s #ne5543p for a Sears projection tv ? They are on the convergence board #A10365 the tv model #is626.54462950 s#75869966 made in 1990in Greensville, TN. |
| Greenville Tenn, very familiar production facilities for Phillips, Magnavox, Sylvania, Philco, and some Sears tvs. |
| QUESTION NO. P120-2: In the projection tv section there have been several mentions of convergence circuits, but in the Zenith 48 inch I am working on no mention is made of convergence. Could Zenith possibly call them something else? |
| Registration Controls & Adjustments. Some of the newer sets require these settings to be adjusted via the service menu [digital] adjustments. |
| QUESTION NO. P122-9: Pioneer 44" projection tv model #sd-p4681-k. When first turned on, the screen will flicker a little and as it warms up the vertical screen widens. |
| Check for poor solder connections on the sweep/power assembly. |
| QUESTION NO. P1231-6: Sony 1271Q Projector. The CRT's are due to be replaced. Is there a low cost source for these? |
| You may wish to contact a crt rebuilder and obtain a quote for these three crts. Otherwise, bite the bullet or check out a newer system. |
| QUESTION NO. P1230-6: Magnavox RFO505AK05 40" projection TV. Intermittent brightness flashes of varying length and a jumpy horizontal (up and down). Also if anyone knows where I can get more info on this older TV. |
| Probably signal processor or tuner problem. Also check the coolant fluid for floaters and bacterial growth; usually shows up more in blue and green but also affects the fluid for the red. |
| TECHNICAL
FYI 10-8-98 This update covers to the following Hitachi
models and chassis SYMPTOM: Intermittent loss of Raster, On Screen Display, sometimes sound. BUT ALWAYS HAS HIGH VOLTAGE! Also removing power and reapplying it again restores operation. THE PROBLEM: There is a lack of a secondary ground for the CRT Dag connected to each CRT board. You can identify this missing ground on the CRT board by locating two vacant pins on each CRT driver board near the CRT socket. The connector is named P801, P831, and P861 relative to each board. The pin nearest the socket is the ground pin in question. The pin furthest from the socket is connected to the cathode of the CRT.
OBJECTIVE: Run a separate ground wire from the "GROUND" pin on each CRT board to the chassis ground. You can use the circuit board mounting screw on the frame under the green CRT. See drawing below. DIRECTIONS: Obtain 3 wires 10, 14, and 18 inches long. The wire is 18 gauge stranded with an insulated jacket. Attach one wire to each ground pin on the CRT socket. Choose the correct length of wire so that all wires will connect to the circuit board mounting screw near the center of the chassis frame.
EXPLANATION: The extra ground is needed if an internal arc occurs in the CRT. This energy must find a path to ground. Before, the only path to ground is through the signal ground wire on the RGB drive connector. This thin wire does not go directly to chassis ground and is inadequate ground for the CRT dag. If the energy level of the discharge is high enough it may corrupt the data flow on the data & clock lines or negatively effect the OSD microprocessor. Since electricity takes the shortest path to ground, the additional ground wire will route the majority of that static pulse to chassis ground quicker and reduce the possibility of corrupting operation of the OSD processor.
|
| QUESTION NO. P1216-3: Hitachi Proj TV Model CT5071 has vertical blue convergence problem. The vertical blue line is still shifted by 1/4" to the left after on-screen tuning. I noticed a similar post on Question# P911-3 and am wondering if the problem was fixed using the recommendations. The unit about 8-10 years old. |
| Check for poor solder connections on the convergence output board, plus any changed value resistors or leaky elect capacitors. Also, some of the active devices, ics and transistors, may be suspect seeing the age of this set. |
| QUESTION NO. P127-2: Toshiba rear projection TV. Will not show both sides of the alignment bars when adjusting the user accessible alignment button. One side of the screen will align vertically and horizontally but the other side will not be. So when viewing the picture one side will be blurry and the other corner is clear. |
| Check the STK 392-020 output ics. Also, the protect fuses on the output pwb. Replacing the ic's should cure the problem. You may try resoldering the pins of the devices, but this is only temporary. The devices breakdown internally. |
| QUESTION NO. P124-8: 42" Magnavox Projection TV model PTV377-AH01 has a dark blue looking mushroom image located in the middle of the screen. Can this be removed? |
| Check the crt coolant chambers for evidence of bacterial growth. The fluid should be clear not clouded [with many particles floating]. If the fluid is cloudy then it should be replaced and the physical faces of the crts cleaned throughly. The other probability is the crts are old enough to become solarized. |
| QUESTION NO. P123-5: Toshiba Big screen rear projection television that works fine except that when you use the user accessable alignment buttons to align the guns via vertical and horizontal lines that appear on the screen when you enter this mode. One side of the screen can be aligned with no problem but the other side is not. Visa versa when you align the other side too. So, you viewing a picture the bottom portion of the screen is blurry and the top is clear. |
| Suspect the STK convergence outputs and fusing devices. STK-392-020 are very common in temperature related failures after a couple of years. |
| QUESTION NO. P1112-2: Pioneer Elite Pro-119 Rear Projection TV. Short but loud static burst when changing channels. Problem has occured twice. The tuner section has been replaced and the static burst goes away. However, when the set needs converging the burst returns after entering the 1st Factory Adj mode and then returning to the normal screen. Cannot find any service mode to adjust the length of the mute between channel changes. |
| Try replacing C541 100uF/35V open. This is the B+ filter to the drive transformer for the deflection output transistor. |
| QUESTION NO. P1113-5: Mitsubishi vs508 front projection TV. 1.6a fuses burn simultaneously on converg board. Changed stk 4273 and checked transistors in line. The fuses do not pop, they slow burn after few seconds. Started checking resistors and changing any suspects but still no good. Is there fail safe way of checking voltage regulators out of board and stk ic's also? |
| If you have time to experiment, you could try this little trick I learned. Typically, an all red/blue/green screen is caused by a cathode to heater short. The reason the screen will stick on one color is because one end of the heater filament is tied to ground. The trick is to 'float' the heater power source. First, measure the voltage across the heater terminals on the CRT PCB. You will need this as reference later. Then take some fairly heavy, well-insulated stranded wire and wrap two or three loops around the exposed core of the flyback transformer. Completely sever the traces on the CRT PCB around the heater terminals and solder the wire you wrapped around the flyback to the terminals. Then power up and measure the voltage across the heater terminals. You will probably have to add more loops around the flyback core until you get a similar voltage to what you measured before cutting the traces. You should have a more or less decent picture now. Simple as that! The one drawback I have noticed in doing this is a slight loss of focus control around the outer edge of the picture which is more noticeable with bigger screen TV's. But what the hey, the set was probably going to be junked anyways, right? |
| QUESTION NO. P1112-8: NEC Projection screen TV. The center "Green" lens has developed a leak and now I am getting a green screen with barely visible images. Is there any way to replace the fluid, or have the lens assembly rebuilt? NEC no longer makes them, has no parts, and offers no tech support. |
| First Question, Where did the fluid go? If it went on either of the main boards or the video output panel then you might as well consider it a lost cause. The material is almost impossible to remove from the pcbs without totally removing all components, deep cleansing of the pcbs, then reassembling AKA Heathkit. The pcbs are not available forn NEC or rebuilders. Second Question, how are the CRTS, this tv is at least 6 to 8 years old. By now, the tubes are crap or have been replaced at least two times. Is it worth it? |
| QUESTION NO. P119-4: Zenith pvr5263mk projection tv has no vertical red. It has horizontal red, also blue and green vertical and horizontal are working fine. |
| Suspect the convergence output devices. They have a tendency, as with other STK devices, to self destruct after a few seasons. |
| Check all the 1/2 watt resistors on the red crt module, there is one on there that is open that is your problem. |
| QUESTION NO. P115-7: I have a Pioneer sd-505 Projection TV which the convergence of the vertical red will not respond. It works fine for a day or so when I replace the resistor to it. What could be the problem, the power pack? |
| Replace the stk pack. they go intermittent inside. |
| QUESTION NO. P115-9: I have a Mitsubishi VF405r Projection TV with at least a bad green yoke. Can I fix it, because I can see where it is burnt, and can get to it, clean it off, etc. How to? Also, what else should I check with this? Actually, all I have right now are the guts. Had to leave the case behind. |
| You can try, BUT a replacement is best. I have never heard if it working. I have probably replaced 100 of these yokes and they are getting harder to find. |
| QUESTION NO. P1028-1: I have a Hitachi projection tv model 60SX1k and the green gun has spread out with erratic lines all over the screen. The red and blue are ok and in the background show up on the picture fine but the green does not merge with the picture at all. |
| Check the convergence output devices. Also, swap the video drive boards from the red or blue to the green to see the if problem is a bad CRT, on the drive board, or in the signal source for the video. If the problem persists in the green with one of the other drive boards, the crt may be the problem. |
| You probably have a bad green yoke, but it may also be a coolant leak. check the circuit boards for crt coolant. |
| QUESTION NO. P1025-3: Mitsubishi rear projection tv. I can find a "character generator, part # 272P00701". ICM and Mitsubishi do not have it. |
| MGA is probably the only source for an ic specifically designated for their use. If they cannot or will not supply the part, the other option is to find an inoperable unit and salvage the device from it's pcb. |
| QUESTION NO. P1023-4: Sony VPH-1030Q1 projector. I need to know how to flip the picture for table top use. Also, the video flickers intermittently. |
| Video flickering can be caused by a problem on the AVIO PCB located @ front, right area of projector. This pcb connects to the external S-Video, BNC, & RCA Jacks. Part # on PCB 1-627-513-12. |
| QUESTION NO. P1013-10: Heathkit (Zenith) GR4500 projection TV. When I adjust the G2 controls on focus module for adequate picture - picture blooms and is out of focus. Focus controls achieve best focus toward end of rotation. Lots of Green Drive, but RED and BLUE have to be put in HI to achieve any light from CRT. HV checks 30K, B+ from 9-151 running 230V instead of 250V specified. Suspect blue and red picture Tubes may be shot - can they be rejuvenated like we used to with three gun tubes? |
| Yes, but do not get too excited. Usually it fixes it for a very short time. Best bet is check cost of new or rebuilt crts, probably $300 + each, if still available. |
| QUESTION NO. P103-6: Sony Rear Projection TV Videoscope XBR model KP-53XBR35. The convergence vertical line is fine, but the horizontal line extends red off the right side and blue off the left hand when the vertical line and center are set correctly. Nasty pin cushion on all four edges (center of each pulled in) and the rgb images are badly misaligned further out from the vertical center line of the TV. Corners are badly misaligned for colors, but not pulled in as badly as the center of the edges. I assume something went bad, but nothing obvious. Is is possible that it simply needs some kind of physical alignment of the guns? I had thought not since the center convergence is good, but I know not much about projection TV's. |
| Remove speaker grill to get to convergence board. There are two fuses on this board. Usually one of them is open. If one is open, you have a bad output IC. No way to tell which one. I would replace both of them and both fuses. I think they are IC1704 and IC1705, and fuses are F901 and F902. Do not touch any of the controls or anything on the picture tubes to try to repair this problem or you will make things worse. |
| IC1704 and IC1705 are no where to be found on the circuit board. However, there are two chips labeled IC904 and IC905 which are physically near F901 and F902. Can anyone verify if IC904 and IC905 are the chips actually referred to? |
| Have exact same set. IC1704, 1705 are on right hand side of board. They are big and should say STK4278L on them. I had/have same problem. Replaced the IC's + simple voltmeter check of + and - 18V supply and check for blown associated caps. No obvious problems. Now same thing has occurred 3 months later. Replacing IC's has again fixed problems but it seems obvious something else is going on. -18volt supply to IC's reads -18.8 when related fuse is pulled and -18.4 when installed. +18volt reads 18.2 (fuse out) and 17.9(fuse in). This (-18v supply) could be the real problem but not sure yet. You can get new STK's from AudioLab in Georgia or B&D enterprises. They are both on the internet. |
| QUESTION NO. P104-9: I cannot adjust the bow or wave out of a Toshiba projection TV model TP55D80. The problem is only with the green adjustments. Also, the major problems are mostly on the left side. The system self-test checked OK. |
| Suspect the convergence output ics. |
| QUESTION NO. P103-8: I have an older (1986) Zenith PV800 series front projector TV that can be switched from top to bottom projection, (floor or ceiling mount). Any advise as to how to perform this operation? |
| There are two big jumpers on the convergence pcb, one for horizontal and one for vertical. Remove them, turn them sideways, then reinstall them. You may have to tweek the convergence a little. |
| QUESTION NO. P923-1: RCA Model # P52750WK Chassis PTK169PABF or CTC169PACG. Projector set down because of a broken A-rf connection on tuner assembly. Set has H, hissing and squealing from blue gun. Checked crt bd, looks ok. Need help. |
| Broken RF connector easily fixed by replacing tuner assembly. You may attempt resoldering the old connector to the tuner, sometimes it works. Hissing from blue crt means you have an hv flash over in the blue crt or at the anode connection. You will probably need to replace the crt assembly. |
| QUESTION NO. P924-11: Sony Projector model # BPH-1000Q. Symptom: Weak or dark picture, possible intermittent video. |
| Remove AVIO panel, located front right side of projector. Check for broken traces @ CJN-202, Video input BNC connector. Connector ground also may need to be resoldered. Seems to be a common problem. |
| QUESTION NO. P921-5: I am working on a Heathkit front projection TV, model GR-8000. This is similar to a Zenith that was manufactured when Zenith owned Heathkit. Do you know if Zenith still supplies modules for this TV? The owner said that soon after he assembled the set, he replaced one of the modules that went bad. When he received the board ,it had a Zenith part no. on the box. The power supply module, no. 235-1152, is bad. This is a Heath number. Any information concerning acquiring modules fo this TV? |
| Check schematics for the Zenith PV-800 through PV-850. I am sure you will recognize the correct PS. Identify the Zenith P/N and they probably will supply it for you. You may try calling Tech Services @ Zenith and ask for a qualified older tech, someone that has knowledge of the Pv series and the Heath counterparts. |
| QUESTION NO. P917-5: I need to know the part number for a transformer. It is from a Zenith rear projection tv power supply. Reference designation on the PCB is TX3501. Can anyone tell me where to get a replacement part and what part number to ask for? |
| Specific part may still be available direct from Zenith but more likely they will try to sell you the complete module. |
| TXG2746 Samsung The original Q-401 in this set was an 2SD1887 even though the print states 2SD1880YD. Replacing it with the original part, 2SD1887 only allows the HV to come up long enough to blow the transistor again. Replaced with a 2SD1885 and have good HV & B+ but E/W pincushion is bad and QE01, 2SA614Y overheats. I will try the recommended CB19 and have already checked RE04, 05, & 07. Also note, the zeners, ZD303/22 volt and ZD305/33 volt can also cause problems. |
| QUESTION NO. P915-9: I have a Hitachi Projection TV model CU500K. It has a Vertical blue line convergence problem. The front cabinet controls for the vertical blue line is turn to its extreme and the blue line convergence is off by more than 1/4 inch. The other two vertical lines will not move over anywhere near the blue line and are fine. Any suggestions how I can correct this. I do not have any schematics to help determine if there is another trimmer and/or a bad cap/filter on the board and which one to adjust or replace. |
| Center the static convergence controls on the front of the set. Readjust the mechanical centering magnets on the neck of thr crt. |
| QUESTION NO. P911-3: I have a Hitachi Model CU5000K projection TV with a vertical blue gun convergence alignment problem. With the front on-seceen blue trimmer at its extreme, the vertical blue line is still off alignment by 1/4 inch. Any suggestions as to how I can resolve this? Is their any trimmer on the convergence board that can be changed to bring this vertical blue line into alignment? Or do I have a bad capacitor? I have not been able to acquire a schematic wiring diagram of the convergence board in question. |
| Center the static convergence control on the front of the unit. Readjust the mechanical centering magnet on the neck of the crt. |
| Suspect any of the convergence output devices and elect caps on the convergence control and output boards. Use an ESR meter to check condition of caps and change questionable ones. Also, check for possible ring cracks at the convergence output devices. As old as this unit is, you may also want to check for bad filters in the power supply circuits. |
| QUESTION NO. P98-2: I have a Zenith projection TV, model no.ZB4685T with a power problem. The unit will not turn on at all. The only indication that it is getting any power is a high pitched squeal that appears to be coming from a transformer TX3501. If this is a common problem with these units please let me know what should be replaced or give me an idea on where to look for the problem. |
| Check hot transistor. If shorted, it is probably a bad fbt or items in derived circuits. HV splitter blocks have been a problem but can be diagnosed by disconnecting the fbt hv lead and powering the unit up. Also, common possibility is shorted diodes in main ps or even a blown audio output; especially if the customer likes all kinds of speakers hooked to outputs. I would bet a ps problem, even a leaky filter. |
| QUESTION NO. P817-11: Are there any books or literature regarding how to convergence on older projection tvs? Using the convergence panel by turning the various pots to bring in the convergence. |
| Data Direct contains most of Sam Goldwasser's writings on how to repair nearly everything electronic as well as these www pages and the postings to ELREPAIR-L electronic repair discussion group. A powerful search engine is included for searching the CD on any topic. See details of the AnaTek Data Direct CD. |
| QUESTION NO. P730-1: Looking for instructions on how to enable the convergence service function on a Mitsubishi VS-5051 rear projector. |
| If the set is digital convergence, then Menu, 2, 3, 5, 9 will enter the setup. However, a good service manual would be beneficial to interpret the codes used rather than just guessing and totally fouling up. |
| QUESTION NO. P729-2: Mitsubishi projection TV has problems with aligning the red color cross hairs to the white ones on the alignment menu. The blue cross hairs line up with no problems. When looking at the red alignment screen, the horizontal line is rotated about 5-10 degrees around the center point in the clock-wise direction (line goes from 190 degree position to 10 degree position.) Sears came out and looked at it but could not fix it. Another company has had it for a week and still has not been able to do anything with it. Any suggestions? |
| Depends on how old your MGA TV actually is, you neglected to give a model number or age. It may be a case of replacing a couple of convergence IC's and touching up the convergence in later models. In older models, it may require checking every electrolytic capacitor and active device in the red convergence circuit, an expensive project because of the time required. After finding the aged or defective components and replacing them, the dynamic convergence may then be adjusted. Also, it is probable, if the set is old enough, and the problem is located in the convergence yoke assemblies, that replacement parts may no longer be available. |
| QUESTION NO. P726-1: Blue gun on Sony Projection TV (KP46XBR25) after warmup has compressed sweep (sweeps from 2-3 inches on either side, therefore converges ok in center but off on both sides). Any ideas? |
| Try the convergence output ics, change both red and blue. Also, may be a defective yoke, rare but I have seen a few in Sony. First I'd suspect the convergence ics. |
| QUESTION NO. P717-2: Pioneer SD-P504 with an apparent pincushion problem. Green convergence controls (PIN and KEY correction) have no effect. Also, the horizontal width (size) control also has no effect. I am stumped on this one. Do not have much experience with Pioneer projections. |
| Check power/deflection pcb for broken or cracked solder connections. Common with many Pioneer Projos. Also, check regulator and convergence output devices as well as current sources for them. |
| QUESTION NO. P629-8: Mitsubishi VS-524RS projection TV when turned on, only the channel indicator comes on. There is no picture or sound. All fuses are good and both relays on the main power board are working. There is not light on either of the CRT guns. This unit has an FM radio section and it also does not work. I tried to switch to test mode but nothing happens. |
| A lot of the older MGA proj tvs seem to have a problem with the yokes breaking down. Seems that the coating around the wires wears thin and arcs. Sometimes destroying the crt at the same time. MGA has a technique for checking the yokes while using a 100 watt light bulb. Also, a common fault seems to be the vertical output ics. Some have fried their way thru the pcbs. Check the condition of the tubes, check the pcbs for signs of overheating or ring cracks. If the tubes are weak consider the age of this tv. |
| QUESTION NO. P618-9: Panasonic projection tv which needs a flyback transformer. Model no CT4600 Part No is TLF14404F. Please tell me where I could get one. |
| Depending how old the set is you should be able to contact any Panasonic parts supplier for components and replacement costs. However, if the set is much more than 7 or 8 years old, some manufacturers fail to supply some components after that period of time. |
| Hitachi Projection TV's - General comment. |
| Some of the tvs have been shipped with poor seals on the coolant chambers. These tvs may function except for a very strange picture. Shaking the set physically will cause the low coolant level to shift indicating in the pix which tube is affected. Most of these sets were already returned to the mfgr. However I have seen a few that slipped thru. Normally the pcbs will not be harmed but the fluid does get to the cabinet base and cause a bit of a mess. |
| QUESTION NO. P430-6: Hitachi CT2033B goes into a "shutdown" state at random intervals. Can be 5 min. to 3 hours. B+ stays, all other voltages drop out. Will stay in shutdown until you turn off power switch for 6 seconds. Then she powers up fine. Have replaced Flyback (twice! on the outside chance we got a bad one), regulator, Horiz. Output, HV cap., all components in the "shutdown" protection circuit. Anybody got any suggestions? |
| May not be relevant but the newer Hitachi proj tvs are having a problem with intermittent shutdown caused by the micro and crystal. Poor solder connections at the crystal and associated components. |
| QUESTION NO. P511-8: CTC169pfa rca proj with very interm startup problems usually from cold start and may be days to weeks apart will pulse on (with hv) then off 3 times then go into x-ray shutdown hv caps at hot have been changed. |
| Change the +15 volt rectifier diode. Monitor the +15 volt at standby and then when the set is running. Causes many nuisance type shutdowns as well as other problems. |
| The 15volt line is a good start, but out of 100's I have worked on, I have had that twice. Measure the reg. 140 volts in standby. If it is above 155, change C4151/C4108 and CR4122 at the same time. The gate drive is probably low. If in doubt, check pins 6&7 of U4101. If the voltages are 10-20% high, this fix will take care of your problem. |
| Hitachi Projection TV's |
| Some of the Hitachi Projection Televisions have been shipped with defective seals on the crts. The indication on screen is a dull or fuzzy display without convergence changes. Removing the screen and inspecting the coolant level or looking under the crts in the electronics area confirms problem. AKA 50UX23B & similar sets. |
| QUESTION NO. P314-5: I have a "Proview" model PV-850 which came to me with no power. I was able to fix the no power symptom but I am left with a Pincushion problem. The front panel controls have no affect nor does the internal Pin-cushion pot. Can anyone point me in the right direction? |
| Possible open or leaky components in PCC circuit, or horiz deflection ckts. Check for proper supply voltages and signals @ active devices. Suspect diodes, transistors, and large [physically speaking] capacitors. Also check thoroughly for probable poor or broken solder connections in same area. Some of the ringing capacitors in hor deflection area have been known to cause excessive width with pcc distortion. Also, poor coupling of the vert correction pcc signal to the PCC ckts may cause problems. BTW is this a Panasonic of Zenith projector, regardless, the general info should be helpful. |
| Hitachi Projection TV similar to 50UX7K. Part Number for PIP smd kit is X480125. Comb Filter has 4 smd caps on it but only 2 affect the video. |
| The 1ufd caps located below the video delay line dry out and knock out the video. Effect is no picture. Other two may cause other symptoms. Check with an ESR Metre to confirm. |
| QUESTION NO. P35-10: I have an NEC projection tv, model # DT 4871S that has a horizontal line across the middle of the screen. I sent the DEF/Conv board (it has the flyback on it) to NEC for repair. It came back with a note that said no problems found. I installed board and set worked for 3 days and then the picture collapsed again. any ideas? |
| NEC consumer electronics do not exist anymore. Only the commercial end of their business and it is probable the tech that rebuilt your board has only seen commercial products. The boards have the vertical outputs, Q 401 & Q402 soldered to it. The heat of the transistors cause the solder to develop ring cracks at the leads. Usually just resoldering those leads will take care of the problem. I usually resolder Q-403, the driver and any resistors leading to the vertical circuit from the derived power sources. It is good practice to completely desolder the leads, clean the pads and component leads thoroughly, then resolder them. BTW, how are the crts, many of these sets became solarized within 2 years of being purchased due to poor design of the crts. I have lost count how many of these sets that I have personally installed all three crts to correct the problem. Then two or three years later do it again. |
| Hitachi Projection using AP-73 chassis. |
| May exhibit intermittaet dead symptom. Resolder the following components: X-100, R-156, R-157, C-126, & C-127. These are under the shield near the mpu. These will, over time if not repaired, cause degradation of the data stored in the memory [E-Prom]. The symptoms may be no audio, no stereo, distorted color, etc. Repair the connections then enter the specific data for the specific model your are repairing. Yes it does vary model to model even when the chassis number is the same. |
| QUESTION NO. P225-5: I have a question about the cooling fluid in rear-projection TV's. After draining the fluid, does the bacteria remain in the fluid chambers? If so, what can I use to flush out the chamber to remove the bacteria? |
| DNA Denatured Alcohol Clean any residue from coolant chambers and from overflow recievers. However, it will happen again, the system is not air tight so the bacteria will come again. |
| QUESTION NO. P213-2: I have a Pulsar 2000E Ceiling mount Projector that has all Zenith electronics. The unit would not hold focus, so we replaced DC Focus block, which corrected the problem. Now we have totally lost our brightness. We have replaced main digital board to no avail. The unit does not want to reproduce the color white. Pulsar is now out of business and cannot provide any help. |
| Probably quite similar to Zenith's PV800 series. It is probable that the CRTs are getting weak not allowing a proper gray scale. |
| QUESTION NO. P210-2: I have a rear-projection Pioneer that clicks both relays when you hit the power button, but has no HV. If you hit the power button again, nothing. When you unplug the unit and plug it back in, it clicks again. I checked all solder joints, and all fuses are o.k. (with no visible signs of resistor or capacitor failure). I suspect the HV transistor adjacent to the flyback, and was wondering if these units had any known problems with symptoms like this. |
| Pioneer has been known to develop numerous ring and surface cracks on both the power/sweep board and signal processing board. Remove the power/sweep board from the chassis and re-solder as many questionable connections that you can find. Then take a high power mag glass and go over it again. Also check the power large resistors in the power supply and deflection circuits for opens. Check all output components for leakage or opens. |
| QUESTION NO. P112-9: Mitsubishi proj. vs4001r is displaying after 3 hrs flashing and loss of sync of red and blue convergence. The solder joints on conv. board were done, it started to work fine as soon as back panel removed, tried heating and cooling brds. Ideas? |
| Thermal problem in defective IC401 ( LA7838 ) causing loss of vert reference signal to the convergence pcb. replace IC 401 & C920 (10uF/100v). Also consider installing a "CM-Kit" to prevent CRT's from being burnt by Horiz. collapse ( usually caused by loose connections @ R505 & HDT). |
| QUESTION NO. P120-2: Zenith J-Line 50" model PV4655LK9. I need to know what type of zener diode CR3408 is on the Convergence Power Supply board. Mine is burned and cannot be read. The schematic I have does not show the diode number. The number of the PCB is 9-553-01. |
| CR3408 is a 11 volt .5 watt zener. |
| Sony KPR46XBR & KPR53XBR plus similar chassis. Symptom: Severe Pincushion Cure: Replace 2SA3101 and 33ufd@160 v capacitor. Items located centre, rear of main chassis. Transistor on large heat sink, cap just to rear of same heat sink. 2SA3102 will also work. Note: Chassis area beneath the transistor may appear charred or discolored. The transistor will be shorted. |
| QUESTION NO. P126-7: I have a Pioneer Projection TV model LS-501 (1982) I have rescued and cleaned all the soot out of. It worked great for around 2 days, then started to collapse vertically into the middle 1/3 of the screen. It now stays there 99% of the time, with occasional good behavior. |
| I bet you did not get 100% of the carbon off the board beneeth the components. Soot [ i.e. carbon black] is conductive, Also, if the boards were covered with soot [?] it is probable some of the vertical components have heat stress damage. Check the coupling capacitors, the diodes, and supply voltages to the vertical area, also look for ring cracks in power deflection circuits. |
| QUESTION NO. P123-10: I am working on a zenith 52" projection. I believe it is a ZB5283RK however the original back is missing. The video has the frizzies or extreme pie crusting and the background color changes slightly. After about 30 minutes the frizzies disappear and the background color stabalizes and the picture is excellent. The picture resembles an arc by a bad crt ground however I cannot hear any arcing. Is this a tripler focus block problem? |
| Inside the anode connectors to the hv block there are supposed to be tension springs into which the hv leads are pressed. If somehow the springs have been lost or removed the hv block will arc internally. You may hear a very slight hiss from set but voulme must be muted. Also the hv blocks sometimes have a way of generating small cracks in the ceramic housing. Moisture impregnates the block and the rest is history. Inside of the tv, front centre just below the screen mounting, there should be small white tags with model and serial information unless someone has physically removed them. Also on the pcb assemblies there are white identification tage that usually start with 9-XXXX for part number indication. |
| QUESTION NO. P120-10: Hitachi Big Screen Model # CT4546. Fuse F903 keeps blowing and i can't seem to find a problem with the main power board. Also all the circuit boards were covered in a thick layer of dust which has since been cleaned. |
| Horiz output, convergence outputs, audio outputs, broken/cracked connections in deflection or convergence circuits. Shorted yokes. Many probabilities. |
| QUESTION NO. P112-6: Magnavox projection TV Chassis PTV300 With a bad Flyback transformer. I need a source for a flyback or a remanufactured board The part # APW008A001 power supply panel. |
| Check with NAP in Greenville, Tenn. They should have the required part if still available. I would check the coolant fluid in the crts before going to far, you may need to change the fluid and clean the crt faces and fluid chambers. If NAP does not have item check with PTS on cost of repairing existing pwb. |
| QUESTION NO. P16-6: I have a Mitsubishi VS-458R Projection tv that has no sound/no raster. The 12volts @ R545 and 170 volts @ R546 are both missing on the MAIN PCB. There is 148 volts @ collector of Q992. I have replaced the HOT, Q591. Using a Sencore Z meter I measured all 3 yokes, and they all measure very similar. All fuses on the power pcb, main pcb and conv.-focus pcb are good, none found blown. Where should I look next? I have the Mitsubishi Service Manual, but it is a bit confusing to follow. |
| MGA has a procedure for checking he yokes dynamically using a 100 watt test lamp. Follow the procedure for locating the shorted yoke, won't always show up using inductive type tester. Highly suspect Green. for some reason, the conductive coating on the neck of the tube breaks down and corrodes the coating of the wires on the yokes. Sometimes removing the yokes and inspecting with a good large magnifier will show the defect. Also sounds as if B+ is a bit high but would be if tv shuts down. Another possible problem is a defect in vertical deflection ckt. |
| QUESTION NO. P128-8: Looking for the value of R-918 on the power supply of a Mitsubishi 50" projection TV. Causes intermittent loss of video but sound ok. Resistor and board are burned and cracked. |
| You may try ICM @ 310-268-1005. |
| QUESTION NO. P129-2: I have a Sony VPH-600Q video projector with a crack in the glass containing the glycol solution. Is there a way to repair the front glass and replace the glycol solution without having to buy the entire crt? |
| Bite the bullet and buy the new crt. |
| QUESTION NO. P1125-4: I have a Mitsubishi VS-4591R Projection unit in the shop. I have replaced the flyback, checked the diodes and various caps, and replaced the HOT. When the unit is powered up the IC protector blows and the HOT shorts. Does anyone know of any common problems with this unit? |
| I had the same problem with a Mitsubishi VS-404. Mits had problem with the yokes on the projection tubes fail. The coating on the windings of the yoke goes bad and causes them to short out. When they fail they usually destroy the horizontal output transistor, blow the main fuse and IC protector. |
| QUESTION NO. P1126-10: Sony VPH-600Q video projector with a cracked green crt. There is a sticker by the crt labeling it as a SD-130G tube. The Sony part number is 8736-05105. Is there a company that sells this crt or is it only available from Sony? |
| Only available from Sony. |
| QUESTION NO. P925-6: I am currently working on 2 Zenith projection TV's. The PVR-5263Rk has the symptoms of it has standby power and audio but no picture. The high voltage cannot be heard coming up. The PRV-5263RK uses a 9-1302-08 SMPS/power supply board The other TV is a Zenith PV-5257RK7 with a power problem also. You can here the smps buzzing and it will get louder when the power button is pushed but no raster or audio with no hi voltage. |
| Suspect the HV/Focus blocks on both of these sets. Try another smps/sweep module first. The HV/Focus a/y tend to develop hairline cracks during operation. Moisture finds it's way in and rest is history. Sometimes the set will exhibit a slight arc or crackling sound. Occasionally the tracking and focus will be the first oblivious clues. |
| QUESTION NO. P919-5: The repair manual for the Mitsubishi big screen TV's are cryptic at best. I have a 60" currently in the shop that simply will not respond to the power command from the remote. The power button works correctly with the VCR and Audio amplifiers so I fairly certain the problem is in the TV receiver end. The local power button responds normally and all other remote functions are normal as well. The VS60VX3 service manual which cost me $50 is little or no help. It appears that the remote signal receiver/relay may be located on the PCB-Cont card. If so the s7800 power contact may be bad. Does this seem reasonable to anyone? |
| The remote receiver may be your fault, however,
use an IR detector card or device to confirm output from the remote while pressing the
desired functions. Try re-initializing the set with the proper commands. Do not go into
E-prom adjustments unless you want a real treat {?}. Another probable item, make sure the
MPU is getting proper initialization command [ voltage ] from the reset circuits at initial power up [ set first plugged in after unplugged at least 1/2 hour ]. Possible defective MPU or device on input to MPU. |
Re: Toshiba Projection E and F Line. Units using Digital Copnvergence. Symptom: Intermittent loss of convergence correction. May happen often or hardly at all. |
Fix from Toshiba as follows: Change C-7668 to .1 mfd mylar or plastric. Located centre front of digital board. Install C-7773 at location marked front left of board. 470 mfd @ 50wv. |
QUESTION No. P627-1: I have magnavox ptv model RJ8530AK03 that the power light is on, no HV. I am not sure if the power supply is defective or HV module. |
Suspect the sweep/power supply module. Check the larger (physically) transistors for short. Also, before going to far check the cooland fluid in the projection assemblies for comtininated fluid. Both are very common problems in these and similar NAP products. |
QUESTION No. P530-1: I have a Mitsubishi VS-404R 40" TV that has sound but no video. Visual check shows that the heaters are not on on the projection tubes. |
Since the filaments are lit I assume that you have HV Also. Slowly increase the screen voltage and check if you have vertical deflection. It is very probable you will not. Inspect the circuit board around the vertical output ic for burnt or broken foil traces. Replace the ic and repair the surrounding circuitry. |
QUESTION No. P58-6: Tengo un Big Screen Mitsubichi modelo SV-4504 dañaado de la fuente (power Supply). Se quemo R918 y necesito saber su valor. |
R-918 is a 1 Kohm 1/4 W. Also check IC-900 and diodes in standy PS circuit. Valuar De R-918 esta 1 Kohm 1/4 W. Tambien IC-900 Y diodes en curcuit de potentia. |
QUESTION No. P418-1: I have a 1991 pioneer big screen tv, model SD-P5043 with a power on/off problem. It will power up the first time with power on button. The next time it can only be turned on by unpluging and pluging back in, it will then come on by itself. The unswitched 5 volt and standby 12 volt checks ok. Also the on/off push button checks ok. |
Could you be having a problem with a stuck relay? When you turn the tv off with the remote does all the functions go away? If so it may be the relay that is used to fire up the set having a stuck hammer, maybe replacing it will fix the problem |
QUESTION No. P214-3: I have a mitsubishi 40 inch rear projection tv model 403R that has a problem holding the blue color when first powered on. You can see blue rings around everything for the first half hour then it corrects itself and does not reappear again until the set is turned off a while. |
Check the stk amplifiers on the convergence board. If they are bad convergence will be intermittent. You can confirm this by reversing the red and blue amplifier. They are the same ic and if the problem is the STK the problem should move to the red. |
QUESTION No. P1029-1: I have a problem with a Hitachi projection TV model #50UX7B. The picture is darker than normal, with streaking trails leading off the the right of contrasty images. Also, the PIP is not working properly but I am not sure if it is related bacause the customer does not use that feature hardly ever and may have failed at a different time. The video inputs on the bad also show the same trouble on the screen, but the monitor output jack has normal video on it regardless of when the input is the tuner or the A/V inputs. |
Surface mount capacitors C217, C201 (both 1uf) and C001 (10uf) in the comb filter module must be replaced. The comb filter module is the metal box soldered into the signal board. (The large board on the left, when viewed from the rear. Also, there are 19 SMD capacitors that need to be replaced in the PIP module, but you may find it easier to just replace the module. Hitachi part number 2375251. It is likely you will have to do both of these repairs to restore the picture to the set. |
QUESTION: What causes the fluid in projection TV picture tubes to go bad? |
Bacterial growth in the fluid. The blue and green light frequencies are more conducive to the growth, whereas the red tends to keep it in check. We first tried those HUGE syringes and sucked it out with tubing down in the reservoirs, but a drill powered pump saves a lot of time. This stuff is basically anti-freeze so dispose of it properly. |
