Quirky 42" Phillips Plasma TV (42PF9631D-37)

[FlyingHigh85]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

I found a few hours to work on the TV over the holidays. I replaced eight of the larger capacitance capacitors (2x 1500microF 10V, 6x 2200microF 16V) on the PSU with new Rubycon and Nichicon capacitors from Digikey. The TV now powers-on and works normally about every three out of five attempts. The other two times out of five I try to power-on the TV and it still has the same problem: it does not power-on and the LED on the front of the TV blinks a 6-3 pattern.

I still don't know what the problem is, but this is a step in the right direction. Before I replaced the capacitors, the TV would only power-on properly in something like one out of fifty attempts. Another bit of good news: I successfully replaced capacitors on a PCB for the first time!!!

After using the TV in question for the past few days, I'm not sure I want to invest anymore time in it. The picture quality of the plasma is pretty good compared to most of the LED TVs I have seen in stores (even though it is a 7-year-old 720p plasma), but this thing runs hot. VERY HOT! Since I live in Florida, USA, I'm thinking I would rather invest in a cooler-running LED TV. Then there is the question of power consumption. I saw somewhere that an LED TV uses something like 1/2 to 1/4 the power of a similarly sized plasma TV.

[FlyingHigh85]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

Update:
Now the TV's audio consistently turns-on, but before the video turns-on, a relay on the psu board clicks once. Then the audio cuts-off and the led on the front of the tv flashes 6x(slow)3x(fast). The led on the psu board is also illuminated. I read elsewhere that this is indicative of a problem detected on the psu board.

I bought a DMM and checked some voltages. There is a sticker on the PDP with a list of recommended voltages: Va=65V, Vsc=-185V, Ve=110V, Vs=197V, Vset=195V. The readings that I saw with my DMM are: Vscan=290mV, Vset=-5mV. As for the Vs, Ve, and Va, these all build to 9V, then a relay on the power supply board clicks once and all these voltages drop to zero over a period of 30-seconds.

I used the DMM to check all the fuses (including 4 on the psu board) and all checked OK. My next step is to try to find some freeze spray to use on the boards attached vertically to the psu board.

I tried disconnecting the audio board, x-main, and y-main one at a time and saw no change. This leaves me to believe the problem is somewhere on the psu board.

[freakaftr8]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

those small boards that are standing up on the power supply. Hit them with freeze spray with the TV doesn't want to turn on and then see if powers up

[FlyingHigh85]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

Since I don't see any obviously bad caps and one or more bad caps on the psu is likely...should I desolder as many caps from the psu as I can and test them with a capacitance meter. Or maybe remove one-half of the capacitors and test with esr meter? I wish there was an easy way to test caps while in circuit.

TV has been on now for ~8-hrs. The heatsinks on the psu must be near 95C, but the caps seem only warm to the touch (~40C). This TV throws-off A LOT of waste heat, albeit I have the brightness at ~90%. I've disconnected the source (a dvd player), but haven't turned-off the tv. I left the house for ~half-hour and the dvd I was playing ended and went to the dvd's menu screen. Now that I've disconnected the dvd player, the screen is dark for the most part, but glowing slightly and I notice some IR due to the dvd menu screen being on for ~30-min.

I wonder how much power this display uses when turned on, but with no source (a dark screen that is only glowing very slightly). *Edit: It seems the tv powers-off if no source is detected. I tried to power it back on, but now have no video. There is audio, and the LED on the front of the tv and on the psu is on steadily. Cycled power to the tv one more time...there was audio, no video, for ~5-seconds, then audio cut-off and the led began the 6-3 flashing again.*

Can't edit previous post, too much time elapsed...

[FlyingHigh85]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

The TV turned-on again today...and has been on for ~6-hrs. I think I've figured out the problem. This time while I was powering it on, I was insulting it. Maybe it just needs to be knocked down a peg or two from time-to-time. I haven't tried hitting it yet, but I think there is a line and physical violence would be crossing it.

Yesterday, while the TV was throwing the 6-3 code, I tried to disconnect the audio board as you suggested, capkid. Sorry I didn't mention it before. It didn't seem to do anything. The TV still gave me the 6-3 error code. No video. Thank you for the suggestion, though.

I scanned the PSU board while I had it out of the TV twice with a flashlight. Like I said, I have an untrained eye, but I didn't see any obvious shorts, damaged traces, or faulty components. On a side note, can anyone tell me what the "clicking" noise is I hear coming from the PSU when I initially plug-in and power-on the TV? There's usually one click when I initially plug it in, and one click when I hit the "power" button. *Edit: so the clicking is likely a relay and indicative of one or more faulty caps.*

I'm part-way through tom66's "A guide to fixing/troubleshooting some common plasma TV problems." While the TV was throwing the 6-3 error code yesterday, I tried unplugging the z-sus and y-sus (or at least what I think are the z-sus and y-sus) as suggested with no positive results, no video or audio, just the 6-3 error code. When I next power-off the tv and it gives the 6-3 code again, I will try to unplug the upper and lower buffers, if I can figure out where they are located...

I will also check the fuses on the PSU (there are four, I believe) with a DMM when it is next powered-off.

I tried plugging the TV in this morning before I went out to run errands for a few hours. It only gave me the 6-3 error code. No audio/video. When I came back, I plugged the TV in and it powered-on. It took ~10-seconds to get video. The TV has been on ~6-hours now and the PQ doesn't seem to have degraded. No led flashes. The led (printed "LED8001") on the PSU board is on steadily.

I tried touching the larger capacitors on the PSU while the TV is on (which, I'm sure, is a smart idea) and none of them are warm to the touch.

I've tried to adjust the video (saturation, color, color temp, brightness, tint) because the reds seem to be much more red than the blues are blue. When I turn-up the saturation, color, and color temp, the blues increase, but so do the reds. Is there some way to increase blues (cooler temp colors) without increasing reds (warmer temp colors) as well? I've included pictures of a LED display vs. the plasma display in question. I was using a point-and-shoot camera for the plasma, but I think I captured the PQ pretty closely to what I see in real-life. The LED display (first pic) is ~1-yr-old and the plasma display is ~7-yrs-old.

[capkid]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

Did you try disconnecting the audio board? I don't want to totally dismiss the PSU, but I went through the same exercise of examining and deciphering error codes. Also, I'd scan the PSU with a flashlight to look for bad components, since the board is densely populated and it can be hard to spot things.

[FlyingHigh85]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

I pulled the power supply out of the tv for a few hours, then reinstalled it. The tv didn't turn-on this time. No video or audio. The LED on the front of the tv is still flashing the 6-3 error code (6 long flashes, followed by 3 short flashes). I heard 1 click come from the right side of the power supply when I plugged the tv in, and another click when I tried to power it on.

According to the service manual, (if I'm reading it right, which is unlikely), my tv is indicating Error 63:

"(Power OK). When this occurs, it means that the POWER-OK line did not become "high." This error is only applicable for TV's with a SDI display, a FHP display or a Sharp full HD display. Depending on the software version it is possible that the detection mechanism of this error does not function and that the TV keeps rebooting."

Since the tv powered-on and worked perfectly for a few hours (until I turned it off), I'm thinking the problem may lie with a "detection mechanism."

I've included a couple of pages from the service manual which I think are relevant in the hopes that someone knowledgeable in the jargon could come to my aid because I don't know where to go from here.

When I had the psu out again, I checked for shorts or any obviously faulty components. I didn't see any with my untrained eye.

[capkid]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

My thought regarding removing the power supply for a short period of time then putting it back in the TV is to see if the result is repeatable on command.

[FlyingHigh85]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

Have you checked the esr of the caps?
Or used a meter to see if any of the FETs are shorted out when it won't turn on?

I'm not skilled in electronics. I had to look-up what ESR and FET might mean. I don't have a ESR meter. Even if I did, I wouldn't know what to look for. I don't know how to check the FETs for shorts.

The only meter I have is a multimeter for around-the-house and automotive use.

I bought the tv in the hopes that there would be some obviously bad caps as suggested above by freakaftr8 and that it would be a simple matter of swapping them out.

[u271D]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

Have you checked the esr of the caps?
Or used a meter to see if any of the FETs are shorted out when it won't turn on?

[FlyingHigh85]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

I powered-off the TV, and then powered-it back on. There is audio, but no video (black screen). There are no flashing LED warnings. The LED on the front of the TV is on steadily. I didn't hear any clicking coming from the psu board this time.

I tried cycling the power for a second time. Now there's no video OR audio. Still no flashing LED warnings. The LED on the front of the panel is just on steadily. I also didn't hear any clicking coming from the psu board.

I tried unplugging the TV. When I unplugged it, I heard one click come from the psu board. I waited a few minutes, then plugged it back in. I heard one click come from the psu and then the led on the front of the screen started the 6-3 flashing again. So I've come full circle. I unplugged the TV, the led continued flashing for ~5sec, then died.

You're probably not going to figure out the issue if you don't turn it off. I'd try turning it off and disconnecting the PSU again.

I'm not sure how this would help. What would I do after disconnecting the psu board again?

[tw2005]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

Could it be something really simple like cracked solder joints, maybe around the heatsink components.

I've seen that in a Samsung which would be fine but could power off at any stage and seemed heat related.

Had cracked joints on some of the FETs, may explain why it mysteriously starting working after you removed it and put it back in.

[capkid]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

You're probably not going to figure out the issue if you don't turn it off. I'd try turning it off and disconnecting the PSU again.

[FlyingHigh85]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

The TV powered-on!

Since I took the power supply board out, I reinstalled it and tried to power-on the TV for sh!ts and giggles. It powered-on with no problems. There was some clicking coming from the power supply during start-up, but there are no more LED flash warnings.

I'm not an AV geek, but the picture and audio quality seem to be GREAT. No pixels out or other apparent serious problems.

Now that the TV has finally powered-on, I'm afraid to turn it off until I find out what the problem is. The previous owner says once the TV powers-on, it won't power-on again for days after it's turned off.

I found a manual for the TV (chassis BJ2.5U-PA) on elektrotanya.com. I'm not a tech, and I don't understand the jargon in the error codes section.

[capkid]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

I had a bad audio board (small board at the top-right when looking at the TV from the back) in a 42PF9431A/37 that had 7 blinks on the front panel and 4 blinks on the alarm board. I found the culprit when I started disconnecting boards to see if I could get the voltages to return; I then got a picture, but I had no sound. So, I guess what I'm saying is that your PSU may be fine. Voltage checks may help to determine whether it's faulty.

I'd first get a copy of the service manual, which is normally available by looking up the chassis ID on the back cover. www.toms-service-manuals.com

Edit: I just noticed that the audio board in your TV is to the right of the board with all the AV inputs.

[FlyingHigh85]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

Picked-up the tv today. Was in garage, had not been powered-on in months. We took it inside, but it would not power-on. Instead the led on the front of the tv blinked 6x slow, then 3x fast. I brought it home, took off the back access panel, took some pictures, then tried to power it on. Now, the led on the front of the tv blinks 7 times slowly and that's it. In addition to this, there is an led on the power supply board that blinks 3 times slowly.

I can't find any obviously faulty capacitors on the power supply board. I understand that this doesn't mean that none of them are faulty. I don't see any 3300microF caps on the board. I've included a few pics. Two of the close-up pics each show a pair of caps. C8088 and c8087 are both 680microF 100V, while c8016 and c8015 are both 1500microF 10V.

The back of the circuit board is very dusty. Should I try cleaning it? With what? I have some 90% isopropanol.

On other forums, some people have reported similar problems with Phillips plasma tvs and most of them say the problem is solved by replacing capacitors. Others say replacing a fuse (there are a few on the different boards) or just the mains power cord fixes the problem.

[tom66]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

If you work carefully you should be fine.
Tip doesn't matter that much.
Anti static procedures may be observed, but TBH it never has been a problem without it for me.

[FlyingHigh85]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

Like I said, I've never done work on a circuit board. The soldering iron that I have for around-the-house use is a 45W Craftsman that advertises a maximum tip temperature of 950F (510C). It is not temp-controlled. I'm afraid this is too hot and I might damage the board. I have a few different tips. Would I be better-off using a pencil tip instead of a chisel tip as suggested in the recapping faq? Also, is it necessary to wear an anti-static wristband in this case?

[munirutech]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

i guess 100$ is cool

[tom66]

Re: Quirky 42" Phillips Plasma TV (42PF9631D-37)

Yeah, they're fine.