| 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: Mitusbishi 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 ckts. |
| QUESTION NO. P725-4: Zenith pvr4663rk projection TV has a color shift. At the covergence 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, truely 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 horizonal 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 colour sync. I would suspect something on the PIP sub assembly or bad smd caps. Specific to the pip circuit only after the tuer 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 conections. 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? |
| 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. |
| 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. |
