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| QUESTION NO. P39-1: Panasonic PC-2033 CTV, chassis NMX-GX. HOT was shorted. Replaced HOT, but now there is still a problem with horizontal. Picture is wavy, especially in the top right corner. |
| Check if Horizontal Output goes hot. If so, check for a ceramic capacitor located near HOT, I think it is .0022 1.5 kv. |
| QUESTION NO. P324-4: I need the service menu codes for Sony KV27V10 TV. Since changing the flyback the picture has become a little distorted. |
| With the set turned off use the remote to enter Display, 5, volume up, power. Then be CAREFULL. |
| QUESTION NO. P329-1: Sony KV27XBR10 TV, horizontal output fails intermittently, B+ ok. Seems to run about 3 days. |
| Check for poor connections on horz. drive transformer, I have seen them bad on a lot of Sony sets. |
| QUESTION NO. P315-5: Zenith sr2568s1 TV has a horizontal line cross the screen. I replaced vert. IC2100. |
| Resistor R-3242 or RX3242 1 ohm or 2.2 ohm opens up near lot. IC LA7837/8. |
| QUESTION NO. P323-8: Sony KV-32V26 TV picture cuts out very randomly (almost seems to happen on high humidity days here in CT). Sometimes a week or two goes by between failures. When working, the picture quality is perfect. When failure occurs, front power-on red LED either blinks (and relay clicks) or is solid on. Also when failure occurs video input mode switches to video 2 every time (which is set up as VHS input). In failure mode, if power-on red LED is blinking, I power TV set off-then on and set is OK. When power-on red LED is solid (in failure mode), switching back to main video IN recovers TV immediately without power cycling. I have heard of the Hstat failures on Sony sets but did not see one on this set. Cleaned HV and anode areas. Noted that red HV wire is routed correctly. Seems like HV is cutting out. When it fails I see a momentary horizontal line before relay clicks and input switches to video 2. |
| Check for poor soldering at the horiz driver transistor, transformsr, horiz output transistor, flyback, and coupling componento to the yoke. Seen a lot of very fine hairline cracks at the driver and fbt on some of these. Eventually causes smps problems. |
| QUESTION NO. P314-8: Would like to know how to arrest lightning affects on televisions through cable/antenna. |
| For lightning on antena - try automotive fusable link somewhere in the line. With cable, haven't tried it but you might be able to use a couple of simple fuses ( I imagine you might have to experiment a little to find a fuse that does not tweak your band width). |
| QUESTION NO. P317-4: Mitsubishi CK 3513R TV had a bright red screen. Tried swapping blue for red made screen blue. Turned down red gun decreased brightness but got retrace lines over entire screen. Last time checked set had alternately red screen and wash-out effect. |
| Bright red, but when swapping drive to crt the screen went blue. Probably not the crt. Check each of the video output transistors and their driver transistors. Check the drive signal from the video processor ic. Confirm bias on the driver transistors and outputs. Suspect defect in bias, akb, drive signals from main pcb to video output section. |
| QUESTION NO. P316-3: Emerson VT1320N VCR/TV, high voltage shut down after 5-15 sec. Set will turn back on, if turned off, then back on. Losing horizontal drive to driver tran. from IC401 M52025SP. Replaced the IC, didn't solve the problem. HV measures 26KV, steady, till shut down. |
| Sounds like set is going into x-ray protection mode. This shuts down the horz.drive. Check to see if the x-ray protect is being enabled. If so, could be a bad flyback or a problem in the x-ray protect circuit itself. |
| QUESTION NO. P317-3: RCA CTC175A F20601SE TV. Audio is very low at speaker. Checked a lot of the electrolytics and two audio transisitors. Also found thermister on degauss circuit laying on circuit board loose from the leads! Repaired that problem but audio will not go very high. |
| The best repair is to replace your epprom. Write down the parameters before you change it. After changing enter parameters in new eprom. Your sound will be fixed ask soon as you install the new eprom however. |
| Defective EEPROM. Before replacing, solder tuner shield grounds and record EEPROM settings. |
| Cut a trace to emitter of q1903. |
| QUESTION NO. P310-1: Toshiba CF2026A TV manufactured 12/91 has an intermittent drop out of channel s 7 & 9 including audio, i.e. narrow horizontal bands appear across the picture with the audio sqealing. UHF channels 14 & up are snowing including cable channels when receiving cable. I contacted Sam's for a Photofact, Toshiba, & Pacific Coast Parts- discontinued 1998. |
| Suggest you remove the tuner and send it to P.T.S. electronics to get rebuilt. Their address should be in most any electronic magazine. |
| QUESTION NO. P222-1: Sharp 27F-S50 TV came in with the following items shorted Q602 horz output tran, IC501 vert output ic, D502 horz p/s diode for vert ic, and blown fuse. I changed the listed items. The set came on for a few seconds, just long enough to obtain raster, then fuse blew and horz output shorted. Removed and swept the IHVT and def Yoke. Both OK. I suspect one or the other but am unable to determine which one is defective. One is breaking down under load, but which? |
| The deflection yoke is shorting under load, when the HV gets to operating voltage it is shorting across to the vertical. You can verify this by installing any good 27" yoke. |
| QUESTION NO. P229-1: Goldstar CBT-9225 TV has no color, just black and white. I replaced the jungle IC (TDA3562 I believe) , a dozen electro caps on the chroma board, the crystal, and still it is b&w. |
| TDA 3651 or TDA3652 are the standard problem with this model. If this hasnt fixed it replaced C502 and X501. You will also then need to adjust the variable cap next to this chip. You must use a insulated screw driver for the adjust otherwise you change the capacitance. |
| QUESTION NO. P225-5: Panasonic TC21DQ TV, HOT keeps blowing even with reduced input. B+ is at 165v, is this right? |
| NO, too flippin high!! |
| QUESTION NO. P223-9: RCA F27701BK-CTC 169 TV has a verticle line, no horizontal. HV and audio are okay. HOT ohm checked okay. All other parts around flyback and osc. seemed to be allright except for .5uf 250.cap. bulging at sides. |
| Horizontal yoke return cap and pin drive transistor. Probably pin diode and cap. Common problem with the 169 chassis. Yoke return will give you horizontal sweep but you will probably have a pincushion problem. |
| QUESTION NO. P125-2: Sanyo DS19350 TV Chassis 19350-00 has sound but no picture just a white line accross the middle of the screen from left to right. Must be ic chip or reg., I need the part and part number. Shrinking picture, resolder the board and the same problem. |
| Sounds like vertical collapse. Check the vertical output I.C for bad solder joints. I do not know the exact location but will most likely be middle of main board and is single inline package 8 to 12 legs mounted on heatsink. |
| QUESTION NO. P224-1: I need a source for parts for an Action TV/VCR. |
| 100-A Exchange Place, Pomona, CA 91768, Tel 909-869-6600, Fax 909-869-5545, E-mail teresacheng@actiontvusa.com, sandygordon@actiontvusa.com. Contact Person Teresa Cheng and Sanford Gordon. Their web site is www.actiontvusa.com. |
| QUESTION NO. P24-3: RCA J25220GG TV with a CTC167M chassis. The color is fine and the picture quality is great but sometimes if you leave it on or turn it off then back on you get different colors in the middle of the screen with outlying areas maintaining perfect color in the program. This is an intermittent problem that freeze spray doesn't detect, nor does taping on the neck of the tube change anything. This problem cannnot be induced when the picture is good and we're unable to get it to go back to normal when the picture goes bad. Looks similar to a convergence problem with the different circles of color in the center of the tube but it has perfect color in all other areas outside of the effected area. |
| Due to the thermal type of problem you describe, I would think seriously about the possibility of a warped shadow mask in picture tube. Somewhere this TV took a jolt or manuf. defect. I cannot see your problem but there is also a degauss circuit that could cause this problem but condition would not change. |
| I have ran into changing purity problems as you describe. The problem turned out to be a leaky B+ diode in the bridge circuit. It was feeding AC into the Degausse circuit. Each time the set was turned off & back on, the purity would change. If manually degaussed while on, the set would look good, til turned off and back on. If the shadow mask is loose, you can verify this by turning on the set and hitting the CRT on the face with your hand, if loose, the purity will shift. |
| QUESTION NO. P218-10: RCA TV chassis CTC169BG. I replaced HOT, Q4401 chopper transistor, CR4401, CR4402, C4401,C4402. When power button LED blinks on & off, and a vert. line blinks in middle of screen from left to right. After some time set will come on and play perfect, until turned off. |
| Believe your problem is connected to the "e" prom. This is a very busy slave. |
| Check the inside of comb module behind shields, rubber standoffs may have deteriorated and contaminated etching side of circuit board causing secondary load on 15 volt supply. This also applies to any other module with shield. You cannot detect anything unless you remove shields. |
| QUESTION NO. P216-5: Sony KVM2130A TV when turned on, the picture is brightness and out of focus. All voltage of driver transformers is high ( B+=135 and it should be 119 v). Checked for bad cap, diode and resistore. I will replace str54041. I do not have a variac, can I build it? |
| Purchase a variac, do not attempt building one, safety and isolation problems in home brews. Try placing a 100 watt lamp in series with the B+ to the deflection. Probably the regulator is the problem. |
| QUESTION NO. P216-1: NEC CT-2505A TV with a vertical problem, retrace lines are visible at the top 3-4" of the screen. It seems that the top 1.5" of the screen is folded over on itself. Is this chassis the same as the CT-2610 as listed in the FAQ (similar problem)? That problem was resolved by replacing the tantalum caps in the vertical section. |
| Very good probablity. Same basic design and component usage. |
| QUESTION NO. P211-6: Sony kv-27xbr50 TV, after 15 minutes to 3 hours it shuts down. There is no set time thus making it hard to test. |
| Check for multiple inferrior solder connections in area of flyback and driver ckts. |
| QUESTION NO. P215-1: Sony kv 2781r TV. Replaced h-out trans and 135 volt reg ic. Worked for couple days then went down. Same components are bad. Replaced both, now set runs but there is a 60 cycle hum, the 135 volt supply willnot regulate. It runs at about 145 volts. I substituted the hot with a 40 watt lamp. The power supply still will not regulate. H-out gets very warm in a hurry. Is it a faulty 135 volt reg? |
| Check for mutiple solder connection faults at the flyback and driver transformers. Also for defective caps in the power supply, esp the small blue ones. |
| QUESTION NO. P211-10: Toshiba cf27c40 TV when turned, on the screen washes out (all white) then it goes into high voltage shutdown. |
| CRT drawing excessive current due either to a fault in the crt or more likely a problem in the G-2 bias level or video ckts. Remove the crt board and see if the set still shuts down. If it does not reduce the screen level, reconnect the pcb to the crt and check again. If the set goes bright with protect then suspect the video ckts. May also be the fbe, screen/focus supply device. |
| QUESTION NO. P211-9: I need replacement devices for a Sears 19" Vertical deflection surface mount devices which are mounted on a ceramic assembly. The device # B905 and D1220 which appears to be surface mount pwr transistors. Also need replacement for AO device small signal transistor which appears to be the driver(s). The total assembly has a JU0069 #M1 number on it. |
| Your set was built by Sanyo/Fisher and you will have to replace the Juoo69 module or the set will just keep failing. I have tried to re-solder that module many times and it just keeps failing, the actual part # is not the JU0069 but most S/F parts distributors know what it is. If it is still available, the part number is 4090140707. |
| Sounds similar to the regulator and vertical components that Hitachi used at one time. If so, these components are not available any longer. |
| QUESTION NO. P119-5: LXI 562.40812950 TV. Picture first started to grow/stretch vertically over about a month's time. Then suddenly horizontal black lines developed, picture stretched severely, and bright multi-colored horizontal line (like concentrated signal) at the bottom. Checked the main board, no heat marks, no apparent bad solder joints. Tried to change input from cable to A/V with VCR to by-pass tuner, no change. Adjusted "Height" adjustment, bright multi-colored line would disapear at bottom, but picture remained severely stretched. |
| Loss of regulation in deflection supplies. Similar to NAP sets in same time peroid. Check coolant fluid also. |
| QUESTION NO. P127-10: JVC C1950 TV came in with no power. Checked all components in the main supply found cr109 in power supply bad and replaced. Turned TV on have power to the screen and audio works but no picture. |
| May be out in left field but some of these, if my memory holds, had problems with the + 9 volt regulator. Seems that regulator feeda many areas. Also, check horiz drive pulses to the output and fbt areas. B++ to crt, etc. |
| QUESTION NO. P127-5: NEC PJ-4600EN(B) 1985 TV the picture does not come in clear, goes in and out. The sound also goes in and out. If I remove the video jack from the FIN2 block on the board labeled H07 4 57 the picture stabilizes but is not quite right. The higher the channel number the worse the reception. Also there is a strip of yellow across part of the top of the picture. |
| Loss of proper bias to tuner, video processor circuits. Failure of multiple electrolytics in supplies. Poor solder connections on the signal and power pcbs. Leakage of crt coolant onto the pcbs. NEC no longer supplies support for these devices and specific components, other than generic, are getting hard to find. BTW, how are the crts? If they are original they are probably in very poor shape. |
| QUESTION NO. P21-1: Sony KV21R1D TV picture and audio are ok. When I switch to Teletext-mode only the frame appears, but no Teletext-page. Is that a hardware-problem or only in the setup of the TV? |
| Probable hardware problem. Does the set work in the closed caption modes? Make sure that modes are properly set. CC/T-T decoder problem or distortion of data - signal coming in from source. |
| QUESTION NO. P22-6: Toshiba CF2034J TV. Replaced bad HOT and blown fuse, turn on power and deflection burns. When deflection yoke connection is removed, there is sound and dot on screen. Problem with deflection yoke or some other component associated with it? |
| Very good probability the yoke is shorting out. I have seen them get so hot that the neck of the crt cracks. Seems more common on the proj tvs than the direct view. |
| QUESTION NO. P127-6: RCA CTC176J2 chassis TV which will not fire when first plugged in. After 10-15 minutes it turns on. We checked the usual (tuner, eeprom). |
| You have loose ground connections. Remove bottom cover of tuner and solder around the frame & the solder stakes that come through the circuit board. Also solder the frame around the CPU and bandswitch i-c. |
| QUESTION NO. P125-7: Symphonic TVCR13F1 TV/VCR. The remote control will not control the functions. All function buttons on the set itself work properly. The remote is putting out a good signal at all times on all functions because I tested it with an infrared card tester. Occasionally, and I do mean very occasionally, the power comes on using the remote control. |
| Check the solder connections at the base of the remote rcvr mod. I have found several loose, causing erratic operation. |
| QUESTION NO. P113-7: RCA chassis CTC169AS, 32" TV, tube seems to be weak on red gun. As contrast is turned up, the red color starts to smear in picture extending past outline of objects, blue and green colors ok. I suspect the tube being bad as it is a 1992 model, but not sure. Is this a board problem or a tube going bad. Also where could I locate a price for this tube? |
| Switch the red and blue or green inputs to the red gun. This will tell you if you have a picture tube problem. If the problem switches to the other gun, the tube is ok. |
| QUESTION NO. P15-7: RCA CTC185AA TV with no menu on screen. I replaced EEPROM 223181(from RCA dealer) and made good ground connection in tuner section. Now TV on OK with on screen menu, but after I did auto search channel, channel will not change. Also, when I changed color (on menu) the vertical size of picture also changed. I replaced almost five EEPROMs already. |
| Solder grounds around tuner frame & shield stakes that come through circuit board. Also solder frame around CPU & bandswitch i-c. If this does not solve the problem, the CPU is not writing the info to the eeprom. |
| How dumb is it to replace 5 eeproms? It is obvious that you have damaged something in the tuner. Go back and look for broken surface mount capacitors/resistors and solder bridges in the tuner. These are very good TV's and respond well to carefull repair work. I have repaired many that came from other shops. Most all were caused by not paying attention to soldering detail. |
| You should look close at the VCO circuit of U1001 and adjust L302 slightly , then try your on screen program again. |
| QUESTION NO. P24-4: RCA ctc 156 TV extreme brightness, no retrace lines, no control over brightness. Boost voltage good, all video signal scopes out good. |
| Check R4701 10~, C4703 47uf/250v, CR4701&02 on 200v line. |
| Check video buffer transistor. |
| QUESTION NO. P24-1: Magnavox RF4800AK02 TV had bad vertical deflection. I traced the problem to a bad resistor (R420, 1/8 watt) next to the power transformer. The 3rd band is damaged so I am not sure what the ohmage should be. The first two bands are brown/black and then it appears to be either brown or black. I replaced it with a 10 ohm resistor and everything works OK. I would like to confirm that this is the correct size. |
| Value of R420 is 1~ 1/3w. The 10~ will probably last a long time, as there is not much current draw in this circuit. |
| R420 is listed in Mag. Man. 7412 as a 1 (one) ohm 1/3 watt resistor. This usually opens when Vert IC 331 is bad. (Old IC P/N 6124440001) (New IC P/N 483520917162). |
| QUESTION NO. P22-7: MGA cs-2193vc TV, when it is cold some channels are ok, some do not work, some pop in and out. After about 45 min to 1 hour the set works fine or after it is on for 2 minutes and I unplug it and plug it in and turn it on it sometimes works. |
| Tap on the tuner. If symptom clears, pull tuner & solder ground connections on the trace side of the board. Be sure and use an iron hot enough to solder to the turner case, usually a 35w. |
| Remove tuner open up and look at posts and other areas for ring cracks. Solder suspect areas and reinstall tuner. If it fails again, check tuning voltages. If there is still trouble, replace tuner. |
| QUESTION NO. P22-8: GE ctc158aa3 TV, picture and sound working fine. Character display is wrong. Some characters become color block or underscores. When pressing channel up key, the channel is changed correctly, but the display of channel number goes like this 11, 11, 13, 13, 15, 15. |
| Remove tuner and resolder ground connections on board side of tuner, around the edges and also metal shields that pass thru the board. |
| QUESTION NO. P110-4: Sony KV32XBR95S TV had a good picture, until it stopped powering up. I found a shorted diode in the audio section and replaced that. Now the set powers up but without any picture at all. Sound is fine. The picture tube and the associated drivers look fine, but there is no video signal. Tracing back, I see the video jungle chip isn't putting out anything but it looks like it does not have the proper inputs. Tracing further, it looks like there is something amiss on the "P4" board - which is the COMB filter. Service manual shows a part number 1195-065 for the board, and the board has both 1195-054 and 1195-045 stamped on it. The schematic for the board does not match the circuit on my version of the board, so I cannot really troubleshoot at the component level. The two ICs on the board are discontinued Sony parts. I would like to replace the board but Sony says they do not carry a replacement anymore. |
| If you replaced D1410 in the audio circuit, also replace Ic140 the audio amp and your set will power up once again. Strange but true! In the future when looking for help always give the part numbers that you have already changed, it makes it easier to look up the repair. |
| QUESTION NO. P124-5: RCA CTC140 TV blank light grey screen comes on but no audio/video. The screen menus and channel display still displays. Same result using all inputs. |
| Try resoldering all 3 legs of q2300 the if amp transistor and usually pins 1-8 of u2300 the IF ic. This usually takes awhile because there are sometimes a lot of poor joints in that area of the board, look it over very carefully it usually fixes these sets. |
| QUESTION NO. P125-6: Sony KV27TS27 TV. After working for a month since the first replacement of Q601 and 602 including the h.o.t. Q502, they broke down again. I checked all of the surrounding components and they all measure o.k. I replaced the parts and the set played for one week them failed again. The supply to the set is 123 V AC. How sensitive is the set to voltage drops and dips? Could the F.B.T have a problem? |
| Check T-604 and R607 a .1 ohm 1/2 watt (goes way up in value). |
| QUESTION NO. P125-4: Hitachi CT2250B TV is dead. Clicks when powered up. I heard that this unit has a problem with a capacitor in power supply. |
| You heard right, check/replace C840 and C841, usually 840 is the bad guy the original is 330uf @16 volts. I use a 330uf at 25 volts, they hold up better. |
| QUESTION NO. P126-4: RCA CTC 187BD2 TV has a slight afterglow problem on CRT after power down. It is light green in color and looks similar to a sidways bowtie above center on the CRT. Recent failure of horizontal output transistor and EEPROM. Aligments complete after their replacement but this afterglow problem still persists. |
| Afterglow in Rca`s sets is normal! This is easily confirmed by calling Thompson if your customer does not believe you. They will tell you the longer it stays on the screen after shutdown the better your picture tube is. |
| QUESTION NO. P21-8: Electrohome 79CH01 TV (made by Mitsubishi). I need a source for discontinued flyback part # 334P16808 as it has a hole in the side of it. |
| Try CRC components, they list it in their flyer but it says call for price the # is 1-800-822-1272. |
| QUESTION NO. P21-2: Proscan P46130WK TV and chassis CTC169PXA. Initially there was intermittant reception on channels above 36, then it went dead on him. I replaced the typically bad CR4118, CR4108, and U4101. Now the power supply works, but at turn on, the unit shuts down instantaneously. B+ only gets to about 60 volts before it shuts down. The HOT and all surrounding components test good. The Xray prot. input of the micro is at normal level, and none of the supplies coming off the flyback are shorted out. |
| Try pulling the anode lead (from the flyback transformer) out of the HV divider block, lay it inside a coffee cup or other non metallic container and then turn the set on. if the set comes up and stays up the HV divider block is bad. |
| QUESTION NO. P22-10: RCA ctc 169ccs TV does not power up at all. The fuse is ok. There is misc voltages across the board but I have no schematic to verify any voltages. I checked diodes in power supply and they seem good. |
| You will probably never fix this chassis without the service manual, there are probably 20-25 known causes for this set being dead.HV divider block, cr 4118, c 4401, c4402, cr4401, cr4402, cr4101, R 4317 etc. etc. etc. get the manual or if your not a qualified tv tech do yourself a favor and bring it to one. |
| QUESTION NO. P22-3: Zenith 21" that has no other identifier that I can find. There is a straight horizontal line across the middle of the screen so I know that I have to replace the vertical section. However, there is no label on anything so I do not know where to find the vertical section. I do not know how you are going to help without the model number. |
| Face the rear of the set and describe the layout of the circuit board/boards. One large board/two boards/three boards, location of the high voltage transformer/ right/left/center etc. Are boards horz or vertical? Look for dates on the components/picture tube/inside the cabinet. Sometimes there is a sticker inside the cabinet, giving the circuit board pt numbers. With this description, someone will recognize the set and be able to help. |
| QUESTION NO. P15-5: ctc185ab TV with a vertical problem. I checked the vertical circuit . It seemed to check ok. The vertical was not filled out at the top about 1'' short. I changed the eeprom. Then went into the factory settings. I do not have a schematic so I had to guess at them. I finally got the vertical to fill back out at the top. But when I tried to get back out of the menu. It popped back down 1'' again. It does this every time I try to set it up. Is there more to the procedure that I am not aware of, or do I still have a problem in the vertical circuit? |
| Make sure you are using the proper eeprom, for U3101, as they all look the same, with the same # printed on the i-c, sometimes with a paint stripe across the #. Call up the service menu and record the data for each service position. Then turn off set and install an eight pin socket. Install the new eeprom pt# 233181. Turn the set on and program the new eeprom with the data recorded from the old eeprom. Check operation of new eeprom by calling up customer menu and adjusting the controls. Turn set off and unplug. Let set for 10-15 min. Plug in and try all functions. If information to new eeprom won't stay, you will have to replace the CPU #233180. |
| QUESTION NO. P126-6: Toshiba CF2665K - TAC 9000 TV, the picture goes black to a thin horizontal line in the middle of the screen. The sound is fine. |
| Most likely C301 and C305 are bad, they are usually 1uf @ 50volt. Some chassis`s are 2.2uf@ 50volt. All of these 25-27`` sets use these caps. They are usually red or brown in color ( different color from the others). |
| Problems in pincushion output, correction, and driver circuits. Check for overheated components and changed value resistors and electrolytics. |
| QUESTION NO. P118-9: CTC187 TV with no voltage on Eeprom P-6. Cannot find the source of this 4.8 v. Changed U1001, U3001, Eeprom, traced all solder connection on replaced IC's, traced this circuit from Eeprom to all IC's connected, including Tuner, Stereo Decoder, PIP IC. There is no short on the line, hokds 4.9 v from external source. I had thought it might have fed thru an IC but it does not. |
| Had same problem and found crystal on u1001 not working properly. Check and make sure that this crystal is oscillating or u1001 will not feed this voltage. |
| QUESTION NO. P126-10: RCA F19201BK TV, Chassis CTC175C with weak sound. At full volume it is at about normal listening level. I checked the speaker, two transistors and all the diodes in the audio section. |
| ctc 175 and other families had common problems with bad connections in tuner, also corrupted the E-prom. Would see different problems and also low audio as you are describing. Two choices, can either replace the eprom and restore normal values or unsolder pin 8 of the E-prom and plug unit in. Use the end of small screw driver to short pin 8 to the pad and power unit on. Once the unit powers up, remove the screw driver. Then push menu button to go to the menu for the speaker control. You will notice that the speakers will be turned off. Once again take your screwdriver and touch pin 8 to the pad while you select to turn the speakers to the on position. Normal volume should return. With pin 8 still to the pad turn the set off -this will allow for the micro to store the info to the e-eprom. With pin 8 still to the pad turn the set back on -normal volume should return--if so turn set off unplug unit and resolder pin 8. |
| QUESTION NO. P119-3: Sony KV-2781R TV originally took more and more time to turn on. Eventually, it took up to 30 minutes or more, and then totally quit coming on at all. I found a defective surge resistor (220 ohm/25W), and a shorted horizontal output. Now there is a wavy green channel display and volume display when activated. The sound is OK, but no picture. Voltages are about 60% lower than normal. 200V is around 90V. |
| There is a .47uf cap in the horizontal drive circuit (on the base of driver?) that can cause this problem. |
| QUESTION NO. P119-4: Magnavox 19L4 series TV chassis. Set dead. Checked voltages at IC430 130 regulator suppose to be 159v in and 130v out. I get 160v in and 167v out. Changed the ic430 regulator, no change on voltage readings. |
| This set is infamous for R502 going way up in value causing dead set symptoms, value is 47k 1/2 watt. |
| QUESTION NO. P114-1: Phillips TV 2b chassis picture is overlayed with rippley bars similar to sound bars. The problem is worse with stronger stations. Checked voltages, appear normal. I suspect maybe a leaky cap. |
| Probably, the tuner AGC does not work. Check the AGC voltage, should be ca 8V with no signal, goes lower at a strong signal. Another possibility is oscillations in the tuner or IF amp, check screens, solder joints and decoupling caps in the IF; remove tuner and inject IF signal from a pattern generator to see if the tuner is at fault. Third, it may be interference from some clock oscillator for the microcontroller, teletext module, nicam decoder or so. Check ground connections, decoupling caps, screens etc. Try removing "unnecessary" modules or stop the oscillators by removing crystals/resonators to find the fault. |
| QUESTION NO. P112-3: Citizen JCTV3403 TV, C3201 blew and I cannot read the value. |
| Capacitor C3201 is a 1mf 160v electrolytic capacitor. |
| QUESTION NO. P17-6: Magnavox TV 25G1 chassis will not start up. Have replaced regulator chip and FET in the switch mode power supply. Disconnected diodes in secondary of smps transformer. Cannot find any shorts or open resistors. Standby voltage of 12v and 5 volts is working. |
| Unsolder pin 18 of IC350. If set now comes on, replace the IC. I have seen this one on 25G1`s & 27G1`s. |
| QUESTION NO. P16-1: RCA ctc 187 TV with the classic buzz. HO was shorted and I replaced it. Running the set at 90 volts the xsistor was getting rather warm. I replaced regulator, driver transistor & cap, also yoke caps & still have the same problem. Also, when the set is cold pix and sound normal but after 5 min or so pix starts pulling in from the sides. I suspect a pincushion problem but I do not have the prints to pin it down. |
| Check the pincushion diode. If it is ok, resolder it. |
| QUESTION NO. P122-2: Zenith SR2552S TV. Vertical defl chip (IC2100) is cracked and broken. I cannot read the numbers. |
| The vertical output number you are seeking is LA7838. The nte cross is NTE7039. |
| QUESTION NO. P121-7: GE TV Chassis CTC175 Series, DEAD. No power from front buttons or remote. Jumped degauss relay to force TV to degauss or turn on, relay clicked, and blew AC line rectifier Diode numbered CR4004. Possibly blew transformer. |
| Solder all your tuner ground. If it is still not working try the eeprom (8 pins IC) U3201. |
| QUESTION NO. P129-10: Sony KV 27 TS 27 TV. Q601, Q602 and Q501 were damaged. I replaced them with no succes. The relay on the set comes in when I plug in the set and then drops off again. When I try to start it through the power button same thing. I checked the entire power supply and everything is o.k. I checked all the components I replaced again and they are still O.K. |
| More than likely R607 a .1ohm 1/2 watt res. is open. Also check q603. |
| QUESTION NO. P1221-3: Toshiba 29" Digital 100H model 2999UXE TV. The picture in the top of the screen and the bottom have a bow. Service menu adjust did not help. |
| Might want to play with the yoke position and wedge insertions beneth the yoke. However, you may compromise the convergence adjustments. I do not think these chassis have dynamic pin correction for t/b of pix. |
| QUESTION NO. P1216-3: Toshiba CF30C50 TV (Chassis 9301). Sound is crackle only 99% of the time. Speakers appear ok, add on speakers do the same thing. |
| Change the MTS, assembly should say MVUS##? on the tag attached. |
| QUESTION NO. P1217-7: RCA TV CTC169L chassis. I need a replacement transistor for Q2906 locator #ctc168/169L series chassis # on transistor is 3474. |
| Video buffer may require a ECG123A or similar. Comfirm base or use the original RCA device. I use a general transistor salvaged from another device but first confirm the base and type {npn/pnp }. |
| QUESTION NO. P1213-3: NEC CT-2610A TV with a vertical problem, retrace lines are visible at the top of the screen. I jumped or replaced all electrolytic caps in the vertical circuit. |
| Replace, do not jump, the two tantalum caps in the vertical circuit with the correct values. |
| QUESTION NO. P1216-2: Sony KV-20TS27 TV. All channels show static for at least 5 minutes in colder weather. Higher range (50+) available before lower range. Video in appears unaffected. Tuner replacement or bad connections? If tuner, source? |
| Connections within the tuner, you may try removing the tuner and resoldering all the ground tabs connecting to the case from the pcb and checking for any other suspicious connections. Tuners available fron Fulton Radio Service in Lansing, MI. |
| QUESTION NO. P1215-1: Toshiba cf2665k TV cuts off after a minute or less. The b+ is supposed to be 115v but is 117v. I did not think this to be a problem but the B+ regulator collector will increase to 70v and this is when the set cuts off. According to Sams this voltage should be 5 volts. I have also defeated the fails safe. When the set cuts off the b+ is never above 117v. The set will play forever at 95v ac in. |
| The problem was the yoke as it was arcing at 115v B+ yet at 90-95v would not. |
| QUESTION NO. P1215-9: Sony Trinitron KV-32TS36 TV the original owner stated if a fan blowing on it from the back was on it would keep the picture. I found a loose solder connect at the C board. I replaced the solder and it was fine for about 6 months. It came back with the picture going on & off frequently. I removed the cover again noticed the same solder connect loose and resoldered. |
| Suggest replacing the component that you are resoldering, throughly clean the leads and solder pads before installing it. |
| QUESTION NO. P1215-6: GE TV CTC175C chassis. Replaced and reprogrammed EEPROM, resoldered tuner grounds. TV will now turn on, but will not even try to scan for a channel. You select channels and get only snow, even on cable hookup. |
| Check for errors in the soldering, or solder splashes or fingers within the tuner. |
| QUESTION NO. P1215-5: Sony KV 27TS27 TV came in with Q601 and 602 damaged. The horizontal out Q502 was also damaged. I replaced them but when I plug in the set I can hear the protect relay click. Also when I power the set by means of the power button, the protect relay engages and the set shuts down (0.5 sec). I rechecked the components I replaced and they are still good. Also is there a way to test the FBT? |
| A good FBT ringer can be used to check the fbt without actually replacing it. Check for vary fine ring cracks around the driver transistor, driver transformer, horiz output transistor and FBT. Also any of the other components in the H deflection may need to be checked. A X 10 or more magnifier may be needed to see the ring cracks. Seems to be a common problem. Does the horiz output or FBT get quite warm when you try to start the set? |
| QUESTION NO. P1129-7: RCA 25'' TV ctc177af or model# F25251WN. I have to replace the whole board somebody damaged it beyond repair. I am not Authorized to repair RCA TV's will I have a problem getting this board. I tried PTS and they don't sell this board. Where can I purchase this board? |
| Directly from RCA via an authorized service location, if it is still available. |
| QUESTION NO. P122-10: Fisher PC-8326 TV with a power supply problem. I thought the power supply was being loaded down so I connected a 40W lamp across 130V voltage read about 40V. Problem used to be intermittent now it is dead with 40V. Checked C7 main filter and opto-isolator D5. Do I have a bad regulator if so how do I bypass or test and where can I get the part. What is the part #? |
| This set is at least 14 years old, you may try Sanyo/Fisher corp for the reg ic but I'll bet it is nla. Many bad solder conections on the chassis and p/s. |
| QUESTION NO. P127-6: I need to know where I can get an obsolete circuit board for a Mitsubishi cs3505r TV board # 930b38001. Old board is broken in half and beyond repair. New board is no longer available. |
| Try Gibson's TV/Video Service @ 810-774-9730. Ask for David, we do a lot of MGA sets and may have a viable board. |
| QUESTION NO. P127-4: Samsung TXE2746 TV does not have full vertical deflection. How do I get into the service menu to access these parameters? I changed the vertical output ic and checked all caps in the vertical and power supply circuits. |
| With set off and using remote, press mute-1-8-2-power on. This will get you to factory mode. Then use the vol up/down and ch up/down to select parameter. For vertical height select va. Make sure you also check r417, r410, d404, dz303 and dz305. |
| QUESTION NO. P123-7: Zenith sls2504 TV will not power up. The customer thought he would repair it himself. After blowing several fuses, he soldered a wire across the fuse holder frying q3431, r3433 & rx3434. Now a cannot determine what to put back. |
| Tell the customer he needs the complete circuit module and order one from the Zenith Parts dist near you. Also, no warranty if he goes into this set again! |
| QUESTION NO. P1130-9: Sony kv27ts27 TV has perfect picture but w/out sound when coax cable is hooked up to the back. But when VCR or DVD is hooked up using audio/video cables, the set works perfectly (w/ sound + picture). |
| Look for small green circuit board labeled sbx1637-xx. Probably has leaky capacitors. DO NOT attempt to repair, just replace. Available as generic from several suppliers for reasonable price. |
| QUESTION NO. P1123-8: Sony KX2501 TV. Need a value for C1902 on cb 1.602.173.11 (burned so badly can't read any id.) (might be the same as C1906 on 1.602.172.11). |
| C1902 is a 330pf @2kv capacitor. Sony p/n is 1-102-327-00. |
| QUESTION NO. P123-9: Zenith TV SR3587DT chassis, looking for cross for video driver transistors labelled C5147 (Q501 to Q503) located on 9-1298-6 board. There does not seem to be an ECG cross. |
| 2SC5147 itself is listed in stock by MCM (800-543-4330; www.mcmelectronics.com); MCM also lists two similar transistors, 2SC4075 and 2SC4544. If insulating hardware is added, an NTE/ECG 376 will also be similar to 2SC5147. |
| QUESTION NO. P123-3: Sony KV-M14U TV. I need the value of and power rating of resistor R852? The one I've removed has lost its color bands, and used to glow orange when in circuit! ;( |
| The first anode (G2) voltage was low at 190V and R852 was smoking. D852 was leaky (Sorry, I don't know the type) and R852 1k ohm was burnt out. Fitting replacements restored the G2 to 880V. |
| QUESTION NO. P111-9: Sylvania RKX185 BK01 TV when the channel is changed, it will not lock on to the new channel until after some time, it will flash about 4 times then will select the new channel. I have replaced the tuner, no change. |
| Try adjusting the AFT pot. It is near the tuner. Turn it just a little at a time and change channels to see the effect. It usually only takes a few minutes to have it in good shape. This is a very common problem with these sets. |
| QUESTION NO. P1130-5: Zenith Z25A11S TV. I need a source for module # 9-1790. |
| From Zenith Parts Department, these boards are now designed to be component level serviced. |
| QUESTION NO. P1130-2: GE 31GT658 TV chassis #CTC187CK intermittently will not power on or off, also has int. vertical problem and gets fuzzy. I replaced vertical IC and all surrounding caps. Could this be IC U3101V? Is this considered the eeprom in this set and if so where can I find it? How do you enter the service mode on this set? |
| Menu, power, volume up, press power then volume up while still pressing Menu button on front panel of set. Typical Thompson On Board Tuner solder connections problem. If you are not familiar with doing this repair and the reference points at the mpu shield then pay a professional. Be aware, the changing of the parameters within the setup service menu can cause the set to go into protect mode. |
| Sounds like the grounds on the tuner and microprocessor (IC# U3101) need resoldering. The Eeprom is IC# U3201 (RCA p/n# 223954 from MCM). Go to this website plop.phys.cwru.edu/repairfaq/REPAIR/F_rcatune.html to see details on doing the resoldering, and on the Service Menu information. |
| QUESTION NO. P1129-2: Daewoo DPBS208GU TV with no supply voltages (dead) since antenna shorted. No fusible component blown. Switching transistor type #KSC5021F-R (mfr # TKSC5021FR) in supply section looks bad. Any cross reference? |
| Samsung's KSC5021F-R is 800 Vcbo, 500 Vceo, 5 Amp, 40 Watt, 15 MHz, Ton <0.5usec, Tstg <3usec, Tf <0.3usec, Cob = 80pF, gain = 15-30. Samsung has sold their power semiconductor line to Fairchild, so now Fairchild is the OEM source. For a cross, try 2SC3750, available from MCM (800-543-4330; www.mcmelectronics.com) or B&D (800-458-6053; www.bdent.com), among others. Or you could try an NTE/ECG 2337. |
| QUESTION NO. P1123-1: Mitsubishi CS-20203 TV. Thin horizontal line runs across screen only, sound ok. |
| Vertical output and associated diode, also may have opened fuse resistor in supply source. |
| QUESTION NO. P1123-7: Where can I find EEPROM preprogrammed for RCA TV CTC187BD and CTC175A? |
| MCM Electronics (800-543-4330; www.mcmelectronics.com) carries RCA Eeproms, p/n# 225688 for CTC187BD and p/n# 217321 for CTC175A. |
| Preprogrammed eeproms are available from several suppliers, BUT they CAN NOT preprogram the tuner. Each CTC185 and CTC175 have their individual program numbers in parameter 100 - 156. These can ONLY be set with the proper alignment equipment. Or you can recover the parameters from the old eeprom. To do this, install an 8pin socket. Install the NEW eeprom, turn on the set, turn off, without unplugging the set, install the OLD eeprom. The set should then turn on. Call up the service menu, write down all of the parameter data (numbers)from the OLD eeprom. Turn off the set, install the NEW eeprom, turn the set on, call up the service menu, install the numbers into the new eeprom. The tuner will then have the factory alignment, otherwise, you will have problems with some channels on reception. |
| QUESTION NO. P1028-9: I need a source for an audio board 8q73016-01t for a ctc169 ptv series from RCA. I would like to replace the whole board since it has burnt out. |
| RCA only, suggest trying to repair original unless it is totally fried beyond any hope. |
| RCA does not sell boards, but there are a few third-party rebuilders that will. PTS or Continental. www.ptscorp.com or www.tvmodules.com Component level troubleshooting is your first option. |
| QUESTION NO. P114-1: Sharp CF25M4 TV, the horiz. output transistor failed after 15 seconds or 2 days of operation. I looked for bad soldered joints but find nothing. |
| Flyback, crt, horiz deflection, B+ to high,? Arcing noise present? |
| QUESTION NO. P118-7: JVC c-s2180m TV has only a horizontal line. All the components seem to be perfect. |
| Perfect one line picture? Then the parts in the vertical can't be perfect. Check output devices & sources. |
| QUESTION NO. P119-6: RCA T19060 TV will not turn on. When the power button is pressed the led blinks but nothing else happens. All the voltages on the switch mode board are at the connectors except 13 volts which feeds the on/off relay. I suspect this voltage should come from the deflection/power supply board but the schematic is very poor. |
| Standby voltages must be available any time the set is plugged in to source. The voltages at the relay coil should be there, otherwise the set will not even attempt to switch on. This voltage comes from the main supply. |
| QUESTION NO. P1118-2: Emerson TS-2587D TV is bright yellow when first turned on. Picture restores when channel is changed. No other symptoms. |
| Suspect broken or cracked connections in the video output section or on the crt drive board. Even poor connections right at the crt socket may cause such strange symptoms. It even may be a data problem but doubtful. |
| QUESTION NO. P1118-1: Sony 27XBR10 TV. B+ is down to 4 volts. There is no HV, and there is a loud, high-pitched whine. I have 167 volts at the output of D601. I am trying to figure out how the feedback loop works. There is .4 volts across the IC652 LED, and Q651 is cut off. When Q651 is cut off, is that supposed to make IC651 increase or decrease the transformer voltage? Is there a data sheet for the STR-S6301A available? Which is the primary of the transformer T651? Pins 5 and 8, or pins 2 and 3? This is the second time the set has failed with the same symptoms. I didn't fix it last time. The guy said he replaced the power supply. I presume that means the F board, but I don't know for sure. The set operated normally for several months after the first repair. Just before it failed, it would occationally drop HV for a couple seconds. |
| Suspect the regulator ic, also check the horiz driv transformat and flyback for very small ring cracks. You will need a good magnifier to see them, probably even a loupe. I would go with the ic and do the connections for sure. |
| QUESTION NO. P1119-7: I require the pin-out configuration for a Matsushita/Panasonic AN5265 IC. It is the audio output IC in a Supra Television. Audio in is ok, no audio out. |
| The pinout of the AN5265 Audio IC is pin#1, Supply Voltage#1 (12 VDC typ.); #2, Sound Input; #3, Mute (0 - 7 VDC, operates at >2.5 VDC); #4, Volume adjustment (0-12 VDC); #5, Filter cap; #6, Feedback; #7, Ground; #8, Sound output; #9, Supply voltage#2 (18 VDC typ.). I suggest checking the two supplies, and the voltages on the mute & volume adjustment pins. |
| Subs to ECG-1789, same pinout. |
| QUESTION NO. P119-1: Symphonic TVCR19E1 TV/VCR. Was dead. Power supply works until powered on then clicks off. I replaced the 6 volt regulator to get it up thus far. Voltages are squirrely at the optisolator IC. IC601 and not sure, without start replacing components I have my 12v, 33v, 5v, and 6v. |
| Replaced capacitor c1026 470Uf@10v. |
| QUESTION NO. P1118-4: Zenith SLV1340S TV/VCR. Was informed unit has Sears PCB's. Unit will not come on, and main fuse does not blow. I need an identity or a cross for Q02 (212 is number on component) located on main tv power pcb. Has d, g, s printed on pcb where component goes. Maybe a FET? |
| Q1002 is a FET and is listed as either a 2SK212E OR 2SK212F. Part # is 2SK212EZ or 2SK212FZ (taken from Zenith parts list). |
| QUESTION NO. P1116-6: GE 09GP107 9" TV chassis TX82MB destroys H.O.T. in about 10 seconds. Power supply is not damaged but AC fuse does blow. |
| Flyback, shorted CRT, defective yoke, defective yoke retrun capacitor, excessive B+. On a 9" TV, how far do you really want to go? |
| Check capacitors in h.o.t. circuit, you should find one open. |
| QUESTION NO. P929-10: Magnavox PR1902C127 TV is completely dead. There are no blown fuses (including the ones soldered to the pcb). I did replace one small transistor (cbc368), but can't find any other components that are bad. When the unit is plugged in, it makes no noise at all. If the power button is pressed, the LED flashes a few times and stops. |
| More than likely the vert. IC is bad along with a few parts in the Vcc line for it going back to the flyback. |
| QUESTION NO. P108-9: GE 20GT324Jx1 TV, chassis CTC175A. I changed the eeprom (dead set) and right now it works. But I have to set the horizontal freq. I tried to go in service mode (technician mode) by pressing power menu and Vol + and it did not work. |
| To access service menu press and hold MENU, then press POWER then VOL +. Use VOL + to get the value lever to 76. Press CH +. You shound see a scrambled pic. Adjust value for a slightly rolling pic. Be sure to check the tuner wrap for poor ground that probably caused the bad EEPROM. |
| QUESTION NO. P1019-6: Need a value for cr 4704 & r4517 in a GE 25GT503 TV chassis # ctc177aa3. |
| CR4704 is RCA part no. 207878, no ECG replacement. R4517 is usually a 22 ohm, 1 watt. The Sams schematic for this chassis calls for a 30 ohm, 1 watt, but most chassis' we have run across use the 22 ohm. |
| QUESTION NO. P1020-7: Zentih SJ1325W TV has a high pitched squeal when plugged it. The H.O.T. appears to be ok, but not sure. Does this H.O.T. have the damper built in? Suspect the flyback. |
| Order the whole module but be sure the CRT is good first. Many of these sets have defective crts. |
| QUESTION NO. P1021-8: Mitsubishi cs-2013r TV only has a horizonal line in the center of the crt. I replaced the vertical deflection ic and no change. |
| Check the supplies to the vertical ic, yoke, and return lines and components, espec any capacitors. Also the PCC circuit may cause problems but not normally total loss of sweep. |
| QUESTION NO. P1022-9: RCA CTC185AB-3 TV does not turn on. I tested an EEPROM from other models but it does not work. For example, I tested the 177 and 175 EEPROM Model, cause the EEPROM for this equipment is not available. |
| The CTC 185 must atain standby mode, that is, with + 5 at the mpu and Eprom to allow access the info via Chipper Checker. Applying external supply to these items will allow communication and diagnostics. BTW make sure the version of Chipper Checker supports the newer Thompson Chassis. |
| This CTC-185 chassis has 1/4 watt 1.5meg ohm near the degauss relay that occasionally goes out.The precise location would be at the rear of the hybrid voltage regulator near a large electrolytic cap. Pull one end out and check the resistance. That usually cures the problem. The color banding is brown-green-green/gold. |
| QUESTION NO. P1021-3: I need a CRT Output IC TDA 8153 for a Sharp SV - 6689X TV manufactured in Spain. I cannot buy this component in Australia and I have searched questlink.com and have not been able to locate this chip. |
| You might try VAAG Electronica HS in Spain (email, hs@vaag.es), their website (www.vaag.es) lists TDA8153, showing 3000+ available at $23.60(US). TDA8153 is also listed on Techsonic's webpage at members.tripod.com/~techsonic5/html. Their email is techsonic@rocketmail.com, but they state a $50 minimum order, so you might wish to check on-line first, if they have any other components you need. |
| QUESTION NO. P1019-2: Samsung 27" CT-3861CA TV. No picture, single thin horizontal line across center os screen. Audio and channel switching ok. |
| Change the vertical output ic and check the supplies. |
| QUESTION NO. P106-10: Zenith SG2589Y TV vertical picture squashed and approximately 2-21/2 inches raised from bottom of screen. Vertical pot just stretches picture. |
| Find the little white tag and order a rebuilt module. 9-XXXX-XX |
| It is not necessary to replace the entire circuit for a vertical sweep problem. Locate the vertical i-c and change any electrolytic capacitors in the same area of the vertical i-c with the same prefix # ie vert i-c 501, replace cap c503, c504 etc. There will also be a main power supply capacitor located near the high voltage transformer, it will also have the same prefix # as the i-c if it is for the vertical circuit. |
| QUESTION NO. P107-2: Aiwa TV with blurred picture with abnormal color apppear on the screen. I check the flyback supply with level 200V but without output. Also perform the adjustment focus adjustment knob of flyback and also adjusted the red, green and blue potentiometer for correct fine tuning of colors on the screen. The result still blurred color picture. |
| Defective crt or focus supply to crt. |
| QUESTION NO. P108-6: RCA F20570WN TV, Chassis CTC166CS. Separate tuner module acts like on-board tuners of CTC 176/177 chassis. Channels 1-6, 14-17, 25-125 seem to work ok. But channels 7-13 and 18-24 lose sync, video, have microphonic type squeals, etc. Problem seems to involve antenna "F" connector of TV. Pushing/moving tight cable connection restores problematic channels, for a few minutes. New cable does not make a difference. The TV, of course, is set for CATV! Is this model chassis prone to this problem (bad soldering in discrete tuner module)? |
| Bingo! Replace the tuner module or attempt resoldering the multiple grounds and other connections. Requires removing from pcb and a good mag glass. Watch for solder spashes and excessive rosin flow. |
| QUESTION NO. P1018-10: Philips 26CE1991 color TV with a focus problem. The circuit I purchaced has no voltage markings shown. I measured the HT as 30k volts and the Focus at 10k volts. A crosshatch picture looks quite normal except for being out of focus. Adjusting the focus control tends to make the focus spark gap arc on the tube. |
| Failure in the focus/G2 devicer circuit/ FBT. Nominal Potential should not be enough to jump the spark gap unless excessive humidity, dust, or a carbon track there is present. |
| The focus voltage is too high. I suspect the focus control is defective. Run a small wire out from the focus pin and measure the focus voltage, while turning the control. It should turn down to about 3 to 4 KV. Most tubes focus @ about 5KV. I have found this problem in several NAP sets. Also check that the bottom of the G2/Focus control is soldered under the HV transformer. If the voltage will not turn down, you will have to replace the IHVT. |
| QUESTION NO. P922-8: Sony KV-27HSR10 TV. The horiz freq is too high. I replaced ic301, the only voltage off is on pin 30 of ic301. It is 3.9v instead of 3.0v. Incoming hori sync pulse are clean. |
| I suspect the surface mount resistor/about the same location where you got your horizontal sync. pulses. It is a 1/8 watt surface mount with a value of 1.8k ohm. But I would advise to use a magnifying glass. Please note that is on the upright board beside your jungle IC. Remove the board that has horiz. sync. pulses on it and you should find it . It may have a 183 written in tiny print/or similar. |
| QUESTION NO P1014-11: Toshiba CF2040J 19" TV. The vertical sweep slowly failed over the course of a year, resulting in a picture that is completely blank at the bottom half of the screen. |
| Toshiba chassis' have the same problem. Replace C301. |
| QUESTION NO. P105-5: Phillips TV Chassis # 19A800-7561. Lightning struck the TV and it has no power. I cannot find any bad fusable resistors and the main fuse is ok. I replaced Q7518 and all the switching Diodes with no change. |
| Check for blown circuit traces (mostly ground traces). |
| QUESTION NO. P97-2: I need data service mode for Grundig T55-549 cuc5302 TV. |
| If this set has a service-mode field (4 digit code) in the OSD, try 8500 as the code (common for most Grundig sets). |
| QUESTION NO. P101-1: Sharp Chas # 21N21-DN TV has a Vert line and I believe the vert IC501 part # X0355CE to be bad but I cannot cross the part to anything. Is there a different prefix I should use to cross Sharp parts? |
| The entire Sharp part number is RH-IX0355CEZZ for that IC. I do trust that (to you) "Vert line" means a line extending left to right across the middle of the screen, for that is what is seen, when a Vertical IC is not driving the vertical yoke. |
| QUESTION NO. P910-6: Toshiba CF2628 TV would not turn on. I eventually performed repairs that brought it up. It now has a very dark screen that is not affected by the brightness or contrast controls. |
| Confirm proper G2 and focus settings and voltages. Proper drive voltages to output devices and at cathodes of crt? |
| QUESTION NO. P927-1: RCA F19201BK TV has a red picture. Swapping the red and blue gun supplies results in a blue picture. What are the commands to enter the service/calibration mode? I have replaced the control IC LA 7610. |
| Newer RCA/GE press volume + and Power @ same time, release power & press channel +. |
| QUESTION NO. P929-3: GE/Thomson ctc187cn2 TV. Upon plug-in, a whine is emitting from the flyback and unit does not power up. Even when crt is unplugged the whine is present. |
| Overload somewhere in the loads can cause the PS to run off freq and squeal. Check for excessive drains from supplies. |
| QUESTION NO. P927-10: Magnovox rj5540 ak01 TV has what seems to be sound bars in the picture and sounds like a jacobs latter. I replaced the horzontial trans. but did not help. The shop before me replaced it and it worked for a while. |
| The service literature for that set says not to replace the flyback, because it is factory adjusted to the board. Maybe thats your problem. |
| QUESTION NO. P923-6: Emerson tc2555da TV, h/o & reg ic last only 10 minutes then short out. |
| Check cap C435 = 1 uF/200V, the horizontal drive transformer and also its solder, and the FBT. Check the resistors off the regulator IC (R503, R507, R521). If the tube is CRT#A63ADG27X, check if it is arcing, which will blow the HOT & regulator IC, etc. |
| QUESTION NO. P827-3: JVC AV32730 TV has no picture and no sound. Sounds like the tube is charging. |
| It sounds like you have a low-voltage power supply problem. Look up the data sheets on some of the larger IC's and verify that the 5-20VDC is present. |
| QUESTION NO. P92-8: Funai F13TRD1 TV/VCR. When powered on I can hear the hv charging the tube. There is no picture and the VCR has no function. |
| It sounds like you have a low-voltage power supply problem. Look up the data sheets on some of the larger IC's and verify that the 5-20VDC is present. |
| QUESTION NO. P920-4: Toshiba 5135DE TV starts up with no sound, sound available after 10 minutes warm up. |
| Check for a coupling cap with high ESR near the amp. |
| QUESTION NO. P917-5: Samsung TXG2746 TV. Blew HOT 2SD1887. Replaced with 2SD1885. Pix returns with reduced width and severe pincushion. HOT does not run hot nor does FBT. |
| The schematic for that set lists HOT Q401 as a 2SD1880. For pincushion problem check CB19 47nf 400v,RE04 6.8ohm 2W,and RE05 also 6.8ohm 2W. |
| QUESTION NO. P917-10: RCA ctc 169 TV. Chopper q4101 and regulator u4101 were shorted due to power surge. Now in standby mode, reg b+ is running 176 volts and the set has horiz. frequency squeal and ringing is present throughout the horiz. and regulator section. I tried q4109,q4106,q4105. The pulse at pin 2 on u4101 is spikes instead of squarewaves. The flyback pulse at base of q4106 is ok but the emitter and collector are wrong. In run mode, the set appears to be ok but the chopper transistor runs very hot. |
| There are three electrolytic caps in close prox of the regulator ic. Change all three items. Also the ic may have sustained damage. C-4102 2.2uf @ 100v, C-4108 47uf @ 100v, C-4104 15uf @ 100v Respective P/N 195691, 193623, 189982. Reg ic is P/N 200419. |
| The problem was caused by a leaky zener diode cr4122 rca#200158. Also replaced at the same time was electrolytic c4108 47uf@50v. |
| QUESTION NO. P917-7: Where can I get a S2000N transistor? It is a HOT for an RCA TV. |
| Try an ECG2354; d1887, or d1885 may work for you. Suggest getting original if you can but these should get unit functionsl if there is no other problem. BTW ECG had a nice cross reference downloadable @ ecgproducts.com, check it out. |
| QUESTION NO. P914-8: Phillips 19" TV chassie # 19s114-00aa. I need the part # for Ic 351 and a source. |
| If the microprocessor is Toshiba made, the part# is 4835-209-17315. If it is Signetics made, the part# is 4835-209-47106. These parts can sourced through; Raybel Electronics 9712 Notre Dame Street, MONTREAL, Quebec CANADA H1L 3R2 Ph (514)352-9071 Toll Free 1-800-361-5970 Fax (514) 493-3481 Fax toll free 1-800-363-3481 Email electroniqueraybel@sympatico.ca. |
| QUESTION NO. P818-2: Sony kv32xbr26 TV, what kind of voltage should I get on the flyback terminal (low voltage side)? Is it ac or dc? When I try to measure it on +15v I did not got any voltage before the diode. I measured the diode resistance, on forward is ok except on reserve. I got only 330 ohm (ru30a diode), is that normal? |
| Negative, Forward can read moderate resistance but reverse should read effectively infinity. Take the diode out of the ckt @ check both fwd and rev readings. The other end of the coil in the FBT is probably grounded. If there is a low resistance load on that particular supply you will read it rather than the true condition of the rectifier. |
| QUESTION NO. P97-1: Pair of Philips 27b800 chassis that the eeproms were bad in. Replaced with factory number, got into service mode and every thing will adjust correctly, vertical height, etc. Once the registers are set, we can exit the service menu exactly the way the manual says, and then unplug the tv to save the registers. We go back in and it is exactly the same as it was when we got started - 06-25-96 menu-->#8-->set parameters-->go to page "I" or #9 to exit, press volume up to save. At this point the screen says SAVED and shuts off, but when it comes back on, the registers HAVE NOT been saved. |
| Bad MPU or initilize ckt? The amin mpu issues the write command following the inkey of the correct command sequence. |
| QUESTION NO. P910-5: Sanyo DS31650 TV, chassis 31650-00 has no sound after a close brush with lightning. The tube had been magnetized but cured itself. The set will have sound for an instant if unplugged with it still turned on. What components in the audio ckt I have checked appear to be OK. |
| Something is telling the MPU or Audio to mute, either a damaged active component in the mute ckt or even the MPU or Memory ics themselves. Blitz does create very unique symptoms. |
| QUESTION NO. P914-9: RCA TV chassis 187AB with tuner on board. Will not work on channels 2 to 50 (bands 1 and 2). Ok channels 51 and up (band 3). Checked tuner shielding both sides of board. |
| Call RCA Tech line, there are a few of these that specific coils within the tuner have high resistance connections. The coating on the coil leads needs to be physically scraped clean and resoldered to the pwb. Hav'nt seen a GoldenRod yet but I'm sure that may be next. |
| QUESTION NO. P914-2: Sony KV-20XBR TV has no output from the speaker jacks. Power amps seem fine, I suspect that perhaps in the service menu, if there is one, that the audio may be turned down or perhaps there is a way to select speakers off. |
| Check the bias voltages to the audio ic and for cracks in the solder connections where the speakers [leads & connector] physically connect to the pwb. Try connecting another set of speakers, of proper impedence, to the terminals. |
| QUESTION NO. P93-4: Sony KV-2765R TV. Picture and sound fine from video and audio input. But when cold, no tuner image or sound. After 30 minutes or so, tv works fine in tuner mode. Sometimes tuner works for 2-3 minutes when I first turn it on, then fails and comes back after 30 minutes. |
| Tuner replacement may suffice. |
| QUESTION NO. P98-4: Panasonic 31 " TV. When power is pressed, all you hear is a wine sound (which I isolated) and discovered that the power transformer was the source. I replaced it, but the problem still remains. No fuses are blown, and other than that sound, the TV depicts no signs of life at all. |
| Whine from the power supply is indicative of some type of overload in the supplied circuits. Check each of the loads for excessive draw. |
|
I have the same problem with a
Panasonic CT-31G10T Chassis AEDP252, and have found the problem to be
the vertical deflection IC LA7836 was shorted from the vertical output
pin 11 to pin 1o ground.
|
| QUESTION NO. P99-10: Zenith SF5262 TV has severe color smear to the right when the contrast is adjusted. |
| I had a similar problem on a Zenith sy2551s, picture was streaky. Found video transistor on neck board Q6184 was shorted, original was 1140 replaced with 2SC3953. |
| QUESTION NO. P818-3: Mitsubishi cs-28exic TV, started to go white, but now it just shows black screen with blue dashes running throug hit. I suspect the video or pip module. There is sound though. |
| Try C-7001 on the PIP module. First press menu on the remote and see if the menu is displayed clearly. If is is then the pip problem may be your problem. The electrolytic eats away the leads on the pwb. You may need to jump the break or run the cap lead to the pad on the other side of the break. |
| QUESTION NO. P824-1: RCA FKC223A TV, Chassis CTC13M. The picture goes out and there is white raster. It is very intermittent, it plays for days and then it appears, sometimes it stays for a while other times less then five minutes. |
| CTC131 maybe? Check the connections on the chopper transistor. Also check for poor connections within the tuner and controller assemblies. |
| Check solder connections on video interface board mounted on left upper corner of cabinet (viewed from back). The three video inputs and tuner video pass through that circuit board. Also resolder connections on MCS tuner control module on pins for plug and wires to tuner module. |
| QUESTION NO. P826-8: Samsung CT-3312V TV. There are white horizontal fine lines (retrace lines) about 2-3 inches wide on the upper portion of the screen and there is also a foldover on the top. I checked all the elect. caps as well as diodes on the vertical sides and all are ok. The vertical diver also outputs the correct voltage 24V. |
| Replace the vertical output ic. If that does not fix the problem it is probable that one of the electrolytic condensers in the circuit are at fault. Seen many of these outputs fail without other causes. |
| QUESTION NO. P826-4: Mitsubishi cs-1983r TV lost audio only. Changed af power amp (ic 301) with no change. Found the 27v vcc to be missing. Cannot locate where the 27v comes from. |
| Problem from the scan derived supplies via a fused resistor and diode. Sorry I can't readily identify the parts and locations. |
| QUESTION NO. P92-4: Zenith System 3 Model #SL2771BG TV. The low channels 2 and 3 are out and 4 through 6 come and go. |
| You may order the tuner or the complete board from Zenith parts. I'd go with the board. |
| QUESTION NO. P93-9: I need the value of R447, in Philips 26c614 TV. Or Nap PRA927 AKO1. |
| R447 is 3.3ohm 1/2watt. |
| QUESTION NO. P817-7: Toshiba cx29711 27" TV chassis tac9165, works for 30 seconds or so then shuts off. If the power button is pressed, it might come back on. |
| Have run across this type problem on numerous brands. Here is the general procedure to try on any set displaying this problem. Use isolated variac to reduce ac input to about 90vac. Monitor the ac current draw. Turn on set. It will generally run at this point. Measure output of VR IC. It should increase steadily as the ac input voltage is increased until the VR IC threshold is reached, then the voltage should stablize. Look in a ECG manual to determine the VR IC voltage if you dont have the schematic. I suspect you will find the following if the voltage does not regulate. Look for cracked solder around the VR IC pins (it is always a good idea to resolder them anyway; high failure area). Check around all the connections in that area, the pass resistors, bias resistors etc. for bad solder. I have found that this will cure 85% of this type of problem. Also ESR any electrolytic capacitors in the VR circuit, even if you find bad solder conn. The heat dries the caps out, and they have a high failure rate. (another 5% of the failures). Replace them with hi temp 105 C electrolytic caps and if possible go up to the next voltage range , if there is room. If this doesnt cure it,be sure to check the solder on the pins of the IHVT, and any resistors in that area (another 5%). Another failure prone area to always check, as well as the horiz driver Xformer connections. Is if there is an electrolytic in the primary of the horiz driver tx,always replace it. It will save you replacing the horis output Xistor. This is a high failure cap. especially in the Emerson & other sets that use it. This is a mandatory replacement item in our shop when ever we service a set that uses it, no matter what the set is in for. Most of them will have a higher than normal ESR after just a few years of service. Again use a HT cap and increase the voltage range if possible. This will cure most of the cases. Be sure to recheck the voltage regulation of the b+ line after the repair. It should hold steady up to 140 vac input or beyond. This is the standard test for regulation in our shop. If you still have problems, then try the horiz shutdown area and the xray prot areas. These test procedures were developed over 30 yrs of servicing. |
| QUESTION NO. P827-6: Phillips TV Chassis model# 19s114-00aa. When plugged in, it comes on by itself and the sound is wide open. I cannot change the channels but the menu will come up. |
| This appears to be the same EEprom or microprosser type problem as I answered in P823-4. See that question for a more detailed answer. This is apparently a common PCE products problem. |
| QUESTION NO. P827-5: Mitsubishi CT 1447LM 14'' color TV. Main fuse blown, found main transistor\ic in the power supply was short. This was replaced (STR 44115) , now the standby light is coming on, but when remote power button is pressed nothing happens. |
| The Mitsubishi are notorious for this. If it is an m3 TV, there are two lots of brown stickdown material. One is by the lopty the other is by the secondary of main power supply. Scrape this off as it becomes conductive with age causing the power supply to blow. Also check the zener next to primary fet as it shorts. |
| QUESTION NO. P823-4: Phillips 19" TV chassis # 19s114-00AA. When plugged in, it comes on by itself with the sound wide open and cannot be turned off. It will not tune any channels but it does have some OSD. |
| I have run across a similar problem (except mine was locked into demo mode)on a B8 chassis. To start with, remove eeprom. This should enable you to normally tune set on & off , change vol, and change channels normally. According to Phillips, if the set now works, or works w/ remote , replace the defective eeprom. If not, replace the microprocessor ic. I suspect that you have the same defective part. For me, replacing the eeprom did the job. |
| QUESTION NO. P823-5: Toshiba cx28400 TV first had only horizontal line. I replaced IC AN 5521 and R 327 5.6 Ohm. I check with multimeter C 308 is still good, not shorted so I do not replace C 308. Now the picture is cut off on the top of the screen. I adjust the trimpot R 352 for height adjustnent. The height can be adjusted, but the picture still cut off about 1 inch. |
| Try changing c301 ,c305, 1mfd caps. |
| QUESTION NO. P812-6: RCA X13101GS TV. What is wrong when your standby bus starts switching from 0 volts to 2 volts after you turn on or turn off the TV? I already tried changing the system controller chip that didn't fix it. The 5-volt supply is fine. When the TV does go on it works fine. I isolated this bus from the rest of the circuit and it keeps on switching. All of the scan inputs start switching as well. It sometimes will stop switching and go on. |
| The one I had fixed was not coming on at all. Turns out it was a small npn transistor (switching type) located in the corner of the PCB. The PCB was slightly browned by it overheating & finally it gave out. New one fixed the problem. You can probably use a 2n3904 too. |
| QUESTION NO. P816-10: NAP TV 19c3 chassis. Need value for R511, cannot read value. |
| 15 ohm 1/2 watt. |
| QUESTION NO. P816-11: Magnavox PR1910C123 TV Chassis 19G6. Problem No audio, horizontal line across screen (no vertical sweep) with a short raster and Q403 output voltage low. |
| Replaced shorted D416 and leaky Z406. Set returned to normal. |
| QUESTION NO. P812-5: RCA ctc169GB2 TV blinks on and off and then goes off completely. After a while it will play a little while then do the same thing again. Changed the regulator (16 pin) and Q4401 chopper transistor. Checked the horizontal transistor, flyback, several caps, dozens of diodes which all checked good,a pile of resistors. There is 140 volts my 5 volt standby and also 13.6 volts and no other voltages. |
| We had an RCA with a similar symptom. Try replacing the HOT, even though it may test good. With our set, if we hit the HOT with freeze spray when the set was acting up it would straighten out momentarily. HOT was developing a short when it heated up. Also, watch the current draw on your variac. You will probably see the set start drawing more current just before it shuts off and starts blinking. |
| QUESTION NO. P728-2: Magnavox TV 25N1 chassis. Set turns off randomly. Have disconnected buttons and remote sensor. Changed micro also diodes in hv shut down circuit. Changed IHVT, no luck. |
| This set is noted for having bad connections around the horizontal driver transformer. |
| QUESTION NO. P812-9: Zenith S2589 27" TV. I need to get into service mode. Menu 9, 8, 7, 6 does not work on this set. |
| If this set was made before about 1992 or 93 it may not have a service menu. Your model number is not complete, the letters after the numbers are needed to hunt this down. |
| QUESTION NO. P77-6: Emerson tc2555d TV, the screen went fuzzy and the words video1 came on the screen. It does not have a video option, I hooked it directly to a cable connection with no cable box and got the same results. The set responds to the remote only for volume mute and recall. |
| Bad Micrcomputer. |
| QUESTION NO. P723-1: Hitachi Model #CT-1951 TV started shuting off a few seconds after power-up. Now it does not come on at all. Power is coming in, fuse is good, power switch is good. |
| Check for drive voltage on the horizontal predriver transistor, normally about.3 volts, be sure you have B+ on the collector of the output transistor,if both are present strongly suspect flyback. Available from Mat electronics at the best price. |
| QUESTION NO. P726-2: Magnavox RJ4910 AK01 TV chassis 25G1-01 - When switching back to the ANTENNA input, from the AUX input, the tuner appears to be dead. Nothing but 'blank/noise' video and 'white noise' audio. RF source is OK. All the DC voltages silkscreened on the pcb side of the tuner are good. All other 'on-screen' adjustments are working properly.Using AUX inputs. |
| The tuner in that set is notorious for going bad. The tuner generates its own tuning voltage and will stick on one voltage. With cable hooked directly to the set, some channel will barely come in, but when channels are changed the same thing is on the screen for several channels. PTS Electronics sells rebuilt ones for $50. with dud. |
| QUESTION NO. P726-4: Panasonic PC29X92S TV, Chassis YAMEDP204. Picture has bright vertical bar about 3" wide on left side of screen. This is not the same as jail bars and has nothing to do with the cathode supply. |
| Check the lead dress of the wires going from the main to the crt drive pcb. Make sure they are not near the yoke leads or near the deflection circuitry. Scope the horiz drive signal and make sure it is not drive related, from the jungle ic or driver stage. |
| QUESTION NO. P730-10: Emerson vt911oa 19" TV/VCR. Good picture but picture flops. No vertical hold. Where can I get a sams photofact for this model? |
| Check with Sam's Photofact site on the net. If they do not have it, you will probably need to get the literature from Emerson. |
| QUESTION NO. P77-8: I need data and where to find an IC for an RCA CTC146C. It has printed on 881-1. In the schematics labeled U3600 op switch ref. |
| Part #179733. Try Union Electronics near Chicago 1-800-648-6657. |
| QUESTION NO. P730-2: RCA x26007wnfo1 27" TV, ctc157a chassis. scr101, and q401f are missing, also cr102 is fried. I cannot make out the numbers. |
| scr101 part #197591, q401 part #190483, cr102 part #176296. |
| QUESTION NO. P729-2: Sony KV-32HSR10 TV with horizontal tearing at the top. The horizontal drive signal had severe jitter. While probing around I accidentally zapped the horizontal output IC (STR-S6301A) and I need a source for it. Two of its pins were dead short. I need to fix the short first, before I can get back to the original problem. Right now I only heard the relay 'click' after turning it on with no sound & picture. |
| Fulton Radio Supply in Lansing, Michigan is a Sony authorized distributor, I know that there are others. Scope the drive signal from the ic, thru the driver, to the gate of the output to see where the jitter and tearing is coming from. |
| Sanken's STR-S6301A is available from B&D Enterprises (800-458-6053) and MCM (800-543-4330), among others. One could also sub ECG/NTE 7046. |
| QUESTION NO. P722-2: Zenith S2589 27" Television. How would I get into service mode? The width is about 1/2 " too wide. Internal width control works but is already at maximum. When set is turned off, I can see a dot in the middle of the screen for a second or two. Are the width and dot problem related? |
| Menu 9,8,7,6 Enter will access the service mode. However, if you have not doen this before, be very careful, write down the settings before changing anything! |
| Check to see if the ferrite core, is at the bottom of the coil. If it is loose inside the core, there in lies the problem. |
| The coil that I am speaking of, is the pincushion coil, brd.# lx3201 in the set that I fixed. Near to the vert. size adjustment. |
| QUESTION NO. P727-6: Zenith SMS1935 TV Chassis #= 9-1244-1A. I replaced the H.O.T. as it was shorted. Found three diodes that were also shorted but I am unable to cross the part numbers on them. The location on the chassis is cr3427, cr3402, crx3425. Looking like a damper, and 2 zeners. |
| May be further ahead just ordering a re-built module from Zenith but make sure the crt is worth the expense. Seen a lot of Zentiths with bad crts. |
| QUESTION NO. P727-2: Source and availabilty for FBT for Magnavox 25N1-01 Chasis 25" color TV OEM p/n appears to be barcode 25737570, alternate # is 00362123-0001. Tried several sources including NTE cross. |
| Try NAP direct in Greenville, Tennessee. |
| QUESTION NO. P726-8: The convergence of Sony KP-46S55 (4 years olds) is bad after the TV was turn on for approximately 10 minutes. The blue color is horizontally displaced to the left about 2 inches. The cross lines for convergence adjustment were merged to form a perfect vertical white line. The horizontal line is also white except about a half inch at both ends have the yellow/orange colors. |
| I troubleshot the pincushion problem and found out one of the three power amps in the IC1704 was internally shorted to -16V at its output (pin #10). This explains why the fuse 902 was blown. Also the blue convergence problem was caused by the lose solder at pin #24 of IC 1705. |
| QUESTION NO. P722-8: Fisher HT870 TV has a picture but has retrace lines across the screen. Also picture has a white tint to it , and color will not adjust the white tint out. Could the picture tube be causing this or something else? |
| If the crt is too weak the akb cannot adjust the bias for the guns to produce a good grey scale nor keep good colour balance. This is very noticable when the scene changes rapidly from dark to light. The retrace lines may be adjusted out using the screen control or may be telling you there is a problem in the screen supply. |
| QUESTION NO. P79-1: Zenith SS6589W2 TV will not power up. Main fuse is OK as well as horizontal output. Relay clicks once when first plugged in. |
| I fixed it myself. Found a bad 100 MF cap at location C3401 next to relay on main power baord. |
| QUESTION NO. P721-7: Sony KV-32S15 TV has sound but no picture (including OSD). High Voltage is OK. Video OK to CRT and I can hear Horizontal sweep circuits. Voltage at pin 5 of CRT should be 460 volts and is 175. Pins 7 and 8 of the CRT are at zero volts (DC to ground). Schematic shows 200 volts (on each?). 135 volts at TP91 is correct. |
| I have since found the problem. R701 (680K) is in series with the screen voltage control and was open. |
| Additional note to Sony television service tip, had similar problem with KV-KV 27exr-10, difference was that the tv would come on and play correctly sometimes for about one hour and THEN the screen image would become black for the first 1/3 of the picture or the first 4/5 of the picture. Problem could be mistakenly diagnosed as a vertical deflection problem. |
| QUESTION NO. P720-6: Sony-kv-27ts27 TV, cannot select between tuner and video inputs. Also sound is always fron aux inputs. |
| Corrupted data from/to MPU or memory ic. Failure of MPU or Memory ic, failure of descrete device on one of the data or i/o lines. |
| QUESTION NO. P720-5: Hitachi Projection TV #CT5061 with a CTC-132D chassis. 3/4 of the way to the top of the screen a red, blue and green line is seen and the picture becomes shrunken beyond this point. I have checked the caps on the chassis and the convergence output board as well as wave forms on this board. All appears well. |
| Any and all of the electrolytic caps from the power source thru the convergence output could cause problems, also some of the discreet ics have been known to fail causing various types of geometry problems. Problem is both Hitachi and RCA seem to be rather reluctant to supply these components any more. |
| QUESTION NO. P720-1: Toshiba CX35C81 TV. How do I enter the set's service mode? |
| Mute, Mute and Menu. Press Mute on remote twice, holding second time and press Menu on front panel of set. Unless you have adjusted these paremeters before do not play with them. The parameters can cause failures if improperly set! |
| QUESTION NO. P72-9: Sony KV-27TS20 TV- color spot problem, only has actual true color in each corner of screen. The rest of the screen is off-color, flesh-tones are high-intensity greens, for the most part. Rotating the unit does not change the spots intensity. However, placing compensation magnets in various locations around the tube will extend the correct color areas out a bit. Is the tube hashed? |
| Have you tried a tube degausser? Usually random color spots are caused by a stronger magnet that was too close to the tv, ex.stereo speakers. If a degausser works turn set off and back on. If the colors are still gone you are fine. But if they came right back check your fround loop strap that circles the back of the tube. Check for cracked solder joints where the loop plugs into the board also. If the colors do not go away or the tv looks like it has been dropped, the tube most likely has gone bad or been damaged internally. |
| QUESTION NO. P77-1: I have had a rash of Panasonic AC Adapters that have come in with no power. |
