Panasonic 42 Plasma no audio no video

[ZZZBruce]

Panasonic Plasma 42" no audio no video. Dated November 2008, Model#TH42PX80U. When A/C is connected the relays click and the red led on lower right corner of “A” board goes on and after a few seconds relay again clicks and red led goes out. When front on/off button is depressed relays click and green leds on SS and SC boards go on, front screen slightly lightens and and front red led goes on. Front red led does not blink. Afterwords, about every 10 minutes the relays will clink with no change--no audio/video. To stop clinking TV must be unplugged. I downloaded the service manual from http://www.toms-service-manuals.com/index.php. I checked the voltages and all appear good/within +.3 to +.4v except as follows. Page 12 Power Supply Standby P12 pins 8&10, SS12 pins 8&10 and SS34 pins1&3 having 13.34v not 12v. Page 15 Power On Operation all voltages appear good. Page 17 Voltages Distribution A51 pin 2 is 4.1v not 5v. Any ideas?
If I need to replace a board any ideas how to identify the board to get the correct replacement and any ideas where to go to get a replacement.

[tom66]

Re: Panasonic 42 Plasma no audio no video

This is most likely A board fault.
I think there's a test which shows it by making the screen full white, but I can't remember what that is. Maybe tw2005 knows.

[tw2005]

Re: Panasonic 42 Plasma no audio no video

No i don't off the top of my head. In fact i picked up an old analogue 42PA60A sounds like a similar issue as yours. Turns on , panel primed and that's it. I did play with it a bit and disconnected the LVDS cable from the D board and had full white. Once i did that the remote inputs blanked out the screen with each input change then full white as it would. I'm thinking bad D board. Not sure if this is what Tom's thinking of.

I was actually thinking of posting for some guidance from you Tom for mine. LOL

[tom66]

Re: Panasonic 42 Plasma no audio no video

This set combines D board into A so you can't unhook LVDS unfortunately, but I still think there's a test which can do it, can't remember it though. Something about disconnecting power from the "A" part of the A board, and leaving power for the "D" part of the A board.

[tw2005]

Re: Panasonic 42 Plasma no audio no video

I'm not much help i'm afraid, is this it?

[tom66]

Re: Panasonic 42 Plasma no audio no video

Is that 2008 panel/guide?
Regarding your panel tw2005 I would actually be going for A board (DG or H I think on these boards.)

[tw2005]

Re: Panasonic 42 Plasma no audio no video

11th Generation Full High Definition Plasma Display TV,TH-42PX80U, TH-50PX80U, TH-42PZ80U, TH-46PZ80U, TH-50PZ80U, TH-42PZ85U, TH-46PZ85U, and TH50PZ85U

[tw2005]

Re: Panasonic 42 Plasma no audio no video

yes 2008 copyright

[tom66]

Re: Panasonic 42 Plasma no audio no video

Not sure if it applies for 2008 720p though.

[ZZZBruce]

Re: Panasonic 42 Plasma no audio no video

My A board is a little physically different from the A board in the picture in the downloaded service manual from http://www.toms-service-manuals.com/index.php. If I am to replace the A board what/where are the identifying numbers on my a board that I would need to get the correct replacement. And Do you have any suggestions where to find a replacement board.

[tom66]

Re: Panasonic 42 Plasma no audio no video

You need to match the TNPA or TNPH number plus the suffix e.g. AH, AJ. Number is printed on the board.

[RonBeanCET]

Re: Panasonic 42 Plasma no audio no video

check on the back for the proper model # small sticker on the curve of the left side, if the model is TH-42PX80U the part # is TNPH0716S, if your model # is TH-42PX80UA The part # is TNPH0716AGS, hope this helps

[ZZZBruce]

Re: Panasonic 42 Plasma no audio no video

Attached is a picture of the A board ID# which is TNPH0716 followed by a "3" in a circle then an "A" in a square with the letters "PbF" in an oval shaped like a lemon above the board ID. DO I need to find a board with the exact numbers/letters?

[tom66]

Re: Panasonic 42 Plasma no audio no video

PbF = Lead (=Pb) Free Environmentally Green (allegedly...) That's a leaf, though I can see the resemblance to a lemon...

TNPH0716 is the board number, but it only refers to the blank PCB with no components. Such a PCB could have many variations in components which are installed.

Try to find a TNPA number and order by that; it may be on the back of the board. If you can't, use the TNPH number but try to order a board which looks identical (i.e. same number of HDMI, same connectors, etc.)

[tw2005]

Re: Panasonic 42 Plasma no audio no video

Going by your first photo of the board, you can see it's rev (suffix) AG but it's known as TNPH0716 AGS from what I can find out using Shopjimmy as a guide

[ZZZBruce]

Re: Panasonic 42 Plasma no audio no video

I have been searching the internet for the board but all sites show it as out of stock including Shopjimmy. In the mean time I am l trying to find out how to be sure it is the "A" board.

Since I am not getting any A/V I imagine doing a Hard Reset would not do anything?

Some people said they replaced the "A" board and after a couple of months it goes out again. I am also thinking of just replacing the TV and parting out this TV. I do not know who would buy these 4+ year old parts (although little working hours) because I do not know if they are working properly.

Thanks for the help from all you guys.