Panasonic TC-P55ST50

[rjr19146]

Im hoping to get some help diagnosing and hopefully fixing an issue I am having with my Plasma TV.

The TV for a while was having ghost menus where the mus would pop up randomly and then just go through the menus randomly. I had someone look at the TV and they said it was possibly the mainboard

This stopped on its own so I figured it was interference or something.

Then the TV just stopped working. There is a clicking noise that comes from the Power Board and the TV just goes from Standby to off to standby to off and never turns on.

Holding the power button on the tv stops the clicking cycle.

I saw a similar issue with the TC-PT55ST30 where it seemed like it was the mainboard (A Board)

So I have two questions - How can I determine for cerrtian if it is the mainboard? I tried using a multimeter but wasnt 100% sure what to look for
so any help confirming that the issue is the mainboard would be great.

The other question / issue is that there do not seem to be any of these mainboard anywhere! the # on the board is TNPH0989 1A

I saw a board TNPH0989 2A for a TC-P60ST50 and was wondering if this board would work. Are there any issues swapping a 1A for a 2A? They look the same..

If this board is not compatible does any know where I could find the board and /or where I can have my board repaired?

I appreciate any help or advice.

Thanks

Russ

[Moreno83]

Re: Panasonic TC-P55ST50

Ghosting menu's is definately a board problem. Might be a overheating problem.

Ill look for a mainboard when i get home

[tw2005]

Re: Panasonic TC-P55ST50

TXN/A1REUUS (TNPH0989UB) is what you should be looking for. 1A 2A is not important.

Board Number : Revision Suffix. The suffix is what determines what model it is for

http://www.ptselectronicsinc.com/txn...-a-tnph0989ub/

[rjr19146]

Re: Panasonic TC-P55ST50

Thanks for the information.

Should I worry that the Overheating is being caused by something other than a faulty board?

Or should replacing the board fix the issue?

[tw2005]

Re: Panasonic TC-P55ST50

Thanks for the information.

Should I worry that the Overheating is being caused by something other than a faulty board?

Or should replacing the board fix the issue?

well unless you can mod it by adding a cooling fan over the heatsink? Some guys have done some interesting things but I've never tried. The A-board can get pretty hot on some of those chips for sure and the BGA solders fracture. My 2010 runs that hot I'm amazed it has not failed too. Very hot to touch.

I'd expect it to work fine after repair but how long before next failure, no idea.

maybe one of the other may have some ideas.

[rjr19146]

Re: Panasonic TC-P55ST50

well unless you can mod it by adding a cooling fan over the heatsink? Some guys have done some interesting things but I've never tried. The A-board can get pretty hot on some of those chips for sure and the BGA solders fracture. My 2010 runs that hot I'm amazed it has not failed too. Very hot to touch.

I'd expect it to work fine after repair but how long before next failure, no idea.

maybe one of the other may have some ideas.

Thanks! Its definitely worth a shot.

[rjr19146]

Re: Panasonic TC-P55ST50

I sent in the mainboard to PTS and they are saying the board tested fine, no issues. Any ideas what else could cause this issue? Otherwise I will need to purchase a new tv....

The power supply board was replaced so it has to be somewhere else.

Thanks in advance

[Hombre]

Re: Panasonic TC-P55ST50

If it was going through menus randomly i would suspect maybe on this side buttons, tried to disconnect it from a-board? But i am not at all familiar with this model so it may not be the problem.

[Neelix]

Re: Panasonic TC-P55ST50 - Not powering on

There is a clicking noise that comes from the Power Board and the TV just goes from Standby to off to standby to off and never turns on

So the LED shows red, then nothing, then red again, then nothing again and continues doing that?

[Neelix]

Re: Panasonic TC-P55ST50

Service manual:

[rjr19146]

Re: Panasonic TC-P55ST50 - Not powering on

So the LED shows red, then nothing, then red again, then nothing again and continues doing that?

That's exactly what happens. Never any picture on the screen just red light click off - red light click off. I noticed if I hold the power button on the side it just does nothing but as soon as i release it goes through this cycle

[vinceroger69]

Re: Panasonic TC-P55ST50

as above post have you tried disconecting the button board? they can play up in odd ways as we have saw a few times on the forum.

[rjr19146]

Re: Panasonic TC-P55ST50

as above post have you tried disconecting the button board? they can play up in odd ways as we have saw a few times on the forum.

I will try to disconnect the button board once I receive the Mainboard back from PTS

thanks for the advice

[rjr19146]

Re: Panasonic TC-P55ST50

I received the main board back and reconnected and then disconnected the button board but the TV still has the same issue

Any other suggestions or troubleshooting tips?

Is it possible it's something as simple as the cord being bad?

Thanks again

[Alastair E]

Re: Panasonic TC-P55ST50

Have you checked for shorts on the SC and the V-SUS line??

First thing I do on a 'dead'/stby Plasma--of Any make...

What made you think it would be Mainboard--Without any testing!!

[rjr19146]

Re: Panasonic TC-P55ST50

Have you checked for shorts on the SC and the V-SUS line??

First thing I do on a 'dead'/stby Plasma--of Any make...

What made you think it would be Mainboard--Without any testing!!

I had Someone look at it when it was doing the ghost menus and they said it was the Mainboard so I assumed since it wasn't the power supply...

I Will try and test the SC and V-SUS line - Will look at the manual to see where these are. Should I just be looking to see if they are getting powered? Or any specific test I should do? (Im sort of new to TV testing/repair, although I have been successful in the past repairing our furnace and Washing machine )

[Alastair E]

Re: Panasonic TC-P55ST50

Aye--That was THEN, NOW you have virtually 'dead' set with blinking LED....
--How many Blinks....??

[rjr19146]

Re: Panasonic TC-P55ST50

Aye--That was THEN, NOW you have virtually 'dead' set with blinking LED....
--How many Blinks....??

There are no blinks. That's why this is difficult to isolate

I was troubleshooting and saw that when the removed power to the main board the clicking stopped. I removed all the connections from the main board and then slowly tested each one and the clicking stops if I remove the ribbon that goes from the mainboard to the center data driver board - not sure if this actually solves the problem....

[Alastair E]

Re: Panasonic TC-P55ST50

Well, It would do wouldnt it!

No mainboard connected to PSU--Therefore Nothing to tell PSU to turn on--Hence, No Clicks!

Be Extremely Careful about removing ANY ribbons to/from the Control-Board and the COF Chips along the screen, especially any wires from the COF to the SC/SS or PSU.

Doing so can Trash a panel COF, and total the set if plugged back while there's still residual power in the source by destroying the chips (COF) that are made as part of the glass PDP...

[rjr19146]

Re: Panasonic TC-P55ST50

Well, It would do wouldnt it!

No mainboard connected to PSU--Therefore Nothing to tell PSU to turn on--Hence, No Clicks!

Be Extremely Careful about removing ANY ribbons to/from the Control-Board and the COF Chips along the screen, especially any wires from the COF to the SC/SS or PSU.

Doing so can Trash a panel COF, and total the set if plugged back while there's still residual power in the source by destroying the chips (COF) that are made as part of the glass PDP...

Thanks. I actually reconnected the power to the mainboard and tested each connection separately to see what connection was causing the clicking. I waited 3-5 minutes between unplugging and replugging

All the other connections except for the Ribbon connection to the data driver did not have the clicking but when I connected the Ribbon to the data driver the clicking started.

Again i'm not sure this solves anything but is it possible this Data Driver board is causing the issue? Is there a way to confirm this is the cause?

Im sort of at a loss since I cant seem to identify the issue. I may look to see if there are any professional repair shops in the area before committing to buying a new tv