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

[FlyingHigh85]

A neighbor is selling a 42" plasma tv that isn't working properly. He says that the tv turns-on and works fine when it is cool, but once it has been turned-on and then shut-off, it takes DAYS to turn back on. Also, when he turns it off, he also has to unplug the tv because LEDs start flashing on the tv.

He hasn't had a chance to show me the tv yet, but I suspect the problem is bad capacitors. I have done a bit of soldering/desoldering, but never on a circuit board, but after reading some how-tos on this site (and others) I think I have all the tools and skills to manage it.

So, I guess my question is: how likely is it that bad capacitors are the problem and is the tv worth his $100 asking price in its current condition?

He bought the tv new in 2006.

[freakaftr8]

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

That model. There are two 3300mfd caps that swell on the bottom of the ps that control low voltage section. Id say very likely.

[FlyingHigh85]

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

Thanks for the input. That'll be the first thing I check when he gets around to showing the tv to me. Worst case scenario, if I damage the board when trying to replace the caps, I think a new ps costs ~$60. I'll likely buy the new caps from here, but what about a local shop, like RadioShack? There's a store right down the street (don't have to wait for shipping).

[freakaftr8]

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

I would get some reputable capacitors. Imho radio shack caps are crap. There will be two you need to change. I believe they are 16v 3300 mfd. Get the 25v 3300mfd. you can step up voltage on capacitors that's not going to change anything its just going to make the capacitors be able to handle more in when you do get new capacitors make sure you get the higher rated temperature capacitors because these capacitors are near heat sinks. Go for nicheons.

[FlyingHigh85]

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

So, these (http://www.digikey.com/product-detai...870-ND/3664365) would be okay? 3300microF, 25V, 10000hrs @ 105C.

[tom66]

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

Yeah, they're fine.

[munirutech]

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

i guess 100$ is cool

[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?

[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)

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.

[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)

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)

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.

[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.

[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?

[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)

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.

[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)

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)

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.