th50px60u panasonic plasma issue

[awyatt2]

i recently aquired a panny plasma that was having problems starting up. was told it would not turn on, well after 8 solid hours of watching it and cycling the power, probing for cold solder joints and finding nothing, i am at a loss. downloaded the manual and entered the service menu and got a clean bill of health.
even though it is a 1080i set and my sammy is a 1080p set the pics are very close. the sammy has a bit better color.
anyone seen this type of behavior before in a panasonic set, supposedly it would turn itself on and off (timer wasnt set, nor clock either) and times it wouldnt start or give a blink code. i have probed it all the way through and found nothing and ran the caps with an esr meter, tried heating and cooling it and found no abnormal behavior. i do not think the owner lied about problems, no one would junk this thing with the picture it has.

[drpj23]

Re: th50px60u panasonic plasma issue

I suppose time will be the best test; those are always the best too.....you got a working TV, but for how long lol.

btw, 1080p and 1080i have the same resolution so they should look the same (well color may differ) but the formation of the picture is different so when a picture is en-motion you'll notice more a blur on the 1080i.
That is why sports channels do 720p instead of 1080i

[Cosmo66]

Re: th50px60u panasonic plasma issue

I had a 50" Samsung plasma FPT5084x that did this to me. It worked fine for about 24 hours after picking it up. Then I couldn't get it to turn on.

[awyatt2]

Re: th50px60u panasonic plasma issue

found the culprit it was the sc board several small caps high esr. they were at the bottom end of the sc board. dont have the numbers handy but will post them later. found them by heating different areas with hair dryer till she came on.not bad 4 hrs and 4.00 worth of parts for a 50 inch plasma, sorry i prefer plasmas to the newer led/lcd's.

[awyatt2]

Re: th50px60u panasonic plasma issue

the caps were c801,c804,c841,c813 near bottom of sc board right at the bottom of heatsink in a straight line. guess after 6 years they dried out, anyway set is 100% now. time to enjoy my new 50 inch plasma.a very merry christmas to all the tv fans out there.

[kc8adu]

Re: th50px60u panasonic plasma issue

i was just about to suggest that.
fixed the sc on a neighbors set a while back.dried out caps galore!
you will find a few on the ss also.

[tom66]

Re: th50px60u panasonic plasma issue

OK, bad caps on a Panasonic.
I am surprised!!

First time for anything, I suppose.

[awyatt2]

Re: th50px60u panasonic plasma issue

Hi Tom, well it was my second panasonic for dried caps. the first was an old crt that the mains cap let go on christmas eve. i will never forget that one. this one had 2 10uf caps one 250 and one 350v. both were dried out 6 yrs of heat i guess led to failure. the tv has been starting every time since replacment. i heated the area with a hairdryer till i narrowed the area then removed them low esr when cold and heat them bang they went up and stablized. it was as the sm said sc board, i call it the ysus panny calls it sc.would do the 7 blink thing when you unplugged it for a while then when you got it on it would continue till the next morning. guessing the caps were dry because after i brought it home it started every time till the next morning. brought it home face up in the back of my pickup.well all said and done merry christmas and good luck in the coming new year.

[swakeem]

Re: th50px60u panasonic plasma issue

Hello and thank you for your post, awyatt2! I have your exact TV (th-50px60U) which recently started powering off on it's own after an hour's usage (occasionally even powering ITSELF back on!), and then eventually, just stopped powering on at all. I read through forums/videos and saw other owners witnessing the "blinking" of the power light. My TV never did the blinking. At this moment, it does not power on (actually no power light appears when i press the button), whether or not i disconnect and reconnect the power cable.

I am an amateur when it comes to electronics, so please forgive my questions or courses of actions taken thus far (which may seem very stupid).

Today I braved up and decided to open my TV (after acquainted myself with plasma TV self-repairs on You Tube), in hopes that I would visually spot any obvious damages (e.g. burn marks on the board, or mis-shaped capacitors). They "visually" appeared ok. I also took out the fuses from the P-board and tested them individually (continuity test) using a multimeter, all of which tested ok.

I came across your post and was intrigued by it. I have some questions if you don't mind:

1) When your problem arose, was your tv able to power on?

2) I understand that you were able to identify the culprit board as the SC board, and the culprit components were the capacitors. You mentioned you did this using a "hair dryer" and an "esr".
(i) Is there any way you can describe the steps taken for this test?
(ii) Was your tv off at the time during the time of the test?
(iii) Were the capacitors attached to the circuit during the test, or were they removed from the circuit?
(iv) What's the "physics" behind heating the capacitors with a hair dryer? (for some reason i figured that heating the boards will result in further failure of the system).
(v) How does the ESR come in? I did some reading up on the ESR to see how it is used to check for a bad capacitor, but non indicated how to check for a bad capacitor whilst in the circuit. So i am starting to wonder if you took out each capacitor and tested them individually (which seems like many across the various boards!).

Your feedback or insight on this matter would greatly be appreciated. Repairman is quoting $400, and I just feel bad going back and buying a new TV when mine is only 5 years old.

[tom66]

Re: th50px60u panasonic plasma issue

This could be relevant?
https://www.youtube.com/watch?v=LjpGKaBt8hg

If you post pictures of the chassis of your TV, we can start helping you to diagnose it.

[swakeem]

Re: th50px60u panasonic plasma issue

This could be relevant?
https://www.youtube.com/watch?v=LjpGKaBt8hg

If you post pictures of the chassis of your TV, we can start helping you to diagnose it.

Thank you Tom for your feedback. I will be opening the TV again within the next two days, so I will get some photos of the entire back of the TV with the panel removed.

Also thanks for the youtube link. I took notes on the symptoms and repair instructions taken by the author. Seems his TV had his power button light blink 10 times (a code that can help identifying what the problem is). Unfortunately my tv's power light does not even light up. Nevertheless, the author does a quick test by cooling down the "FET" (had to google "FET" to get an idea on what it is) driver IC that supplies 15v to the A-board, which allowed the TV to power on (so i guess that's how he identified that it was the problem). Hopefully my Power Supply unit contains a similar chip so I can experiment with in the same manner.

Once I get access to the TV's circuitry, I'll snap a photo and hopefully you can guide me in a direction. Thanks a million.

[johnboy1313]

Re: th50px60u panasonic plasma issue

The 42" cousin of your TV has a thermal fuse in the transformers. Is it possible that your TV has a similar issue and this thermal fuse has failed killing your power supply? There's a YouTube video that shows how to test and repair although the video's creator is chasing a 7-blinks issue. Maybe your power supply has a failed transformer in the Standby circuit???

http://www.google.com/url?sa=t&rct=j...r-wOHD_cweNZTA

[swakeem]

Re: th50px60u panasonic plasma issue

This could be relevant?
https://www.youtube.com/watch?v=LjpGKaBt8hg

If you post pictures of the chassis of your TV, we can start helping you to diagnose it.

Hi Tom. Sorry for the delay. Attached is the picture of the chassis. I ordered a power board from a company called TSM Inc in hopes that it might fix the problem. I replaced the power-board today, but that didnt seem to solve the issue. When i pressed the power-button, the power light went on for two seconds, the tv clicked once, and that was it. Power light never went on again (even after disconnecting/reconnecting the power cord).

[swakeem]

Re: th50px60u panasonic plasma issue

The 42" cousin of your TV has a thermal fuse in the transformers. Is it possible that your TV has a similar issue and this thermal fuse has failed killing your power supply? There's a YouTube video that shows how to test and repair although the video's creator is chasing a 7-blinks issue. Maybe your power supply has a failed transformer in the Standby circuit???

http://www.google.com/url?sa=t&rct=j...r-wOHD_cweNZTA

Hi Johnboy, thank you for your feedback. It could be the problem as stated in the youtube link you provided. The only difference is that as you mentioned, the video author's LED is blinking, while my TV's is not even lighting up. I also changed the power board with a (supposedly) functioning one. To no avail.

[tom66]

Re: th50px60u panasonic plasma issue

Can we get a close up of power board?

[awyatt2]

Re: th50px60u panasonic plasma issue

sounds like the power supply was working until you powered it up. you will need to find a short on one or more of the other boards. a short is the only reason i can think of that would take out a working power supply. tom is the resident expert on finding the shorts on the other boards. the short is probally what killed the first one.
i am back to working on the newer panny i just got a th50px75u. missing entire top half of picture but the display has got the "glow" in the upper half resorted to pulling out the 2430a tektronix on this one.

[tom66]

Re: th50px60u panasonic plasma issue

Pretty uncommon for a short to kill a PSU. Will normally go into protection mode. I've NEVER had a short kill a board. And I'd be surprised if Panasonic had an issue with that.

[swakeem]

Re: th50px60u panasonic plasma issue

Hey Fellas,

Ok, I am attaching two photos of the Power Supply Unit.
Photo#1 (PSOriginal.jpg): The original power supply unit
Photo#2 (PSNew.jpg): The replacement power supply unit

Is there any chance the issue could be the PA board?

[tom66]

Re: th50px60u panasonic plasma issue

Check voltages going into PA board.
Check against SM:
http://www.tgohome.com/ServiceManual...&Search=Submit

Or training guides:
http://www.tgohome.com/ServiceManual...&Search=Submit

[swakeem]

Re: th50px60u panasonic plasma issue

Hello Tom66,

Thank you so much for your response and for providing me the training guides.

They were extremely helpful and definitely tied many of the loose ends, especially with my limited technical knowledge.

I am attaching the "No Power Troubleshooting" flowchart which was illustrated in the training guide (page 39):

http://www.tgohome.com/ServiceManual...&Search=Submit

My questions on this flow chart pertain to, for example, when it states "Is there 2.5V at pin 13 of the connector P25 on the P board?". My questions are:

1) If the P25 connector is already in connection (via cable) to another component on the board, how will i be able to measure the voltage, granted that I will not have access to an exposed pin? If I remove the cable connection, then that will break the circuit to the other boards. Am I missing something?

2) Assuming i can get to pin13, this will connect to the positive terminal of my voltmeter. Where will i connect the negative terminal of my voltmeter to?

3) Does the pin numbering go in the following order (from top to bottom)?:
1 2
3 4
5 6
7 8
etc...

Thank you very much in advance.

Sami