Panasonic TC-P42GT25

[mpj31]

After reading many threads and a lot of Google searching I still cannot find where to start on repairing my Panasonic Plasma, Model TC-P42GT25. I turn it on and it has 1 blink... then I hold power and get 10 blinks.

Best thread I can find similar might be this:
https://www.badcaps.net/forum/showthread.php?t=28207

No solution found. Seems as if its probably the A board. Could I then just order an A board on ebay and see how it goes? Doesn't look too outrageously expensive?

[Gatedmk4]

Re: Panasonic TC-P42GT25

What fault is your TV showing? if you send more diagnostic information we can help you a bit more. Every repair is different.

[mpj31]

Re: Panasonic TC-P42GT25

Sorry to be more specific. The TV does not turn on and I do not get picture, I do however hear a couple clicks as I have always heard, whenever I turn it on, and then the screen remains black. I do get power to the TV. The LCD red power light just blinks. "I turn it on and it has 1 blink... then I hold power and get 10 blinks."

Does that help?

[Gatedmk4]

Re: Panasonic TC-P42GT25

OK so I assume you are talking about your power LED on the front of the TV. It lights up then goes to 10 red flashes?

[tw2005]

Re: Panasonic TC-P42GT25

might pay to check out the SC board and see if there's a short across SC2.

The other thing i've tried with A-boards is disconnect all power from the SC, SS and c boards, disconnect the white ribbons from the A-board that go to the Sc and c boards, power up and see if it's still SOS1.

On the 2010 model I tried it on it , the a-board started normal with no error blinks.

let the power bleed off a while before you reconnect the SC,SS and c boards. you can spike them especially the c boards. I killed a samsung panel once spiking those c boards or the samsung equivalent of them.

could always check with a meter to see what residual voltage may be still stored on the PSU.

[mpj31]

Re: Panasonic TC-P42GT25

might pay to check out the SC board and see if there's a short across SC2.

The other thing i've tried with A-boards is disconnect all power from the SC, SS and c boards, disconnect the white ribbons from the A-board that go to the Sc and c boards, power up and see if it's still SOS1.

On the 2010 model I tried it on it , the a-board started normal with no error blinks.

let the power bleed off a while before you reconnect the SC,SS and c boards. you can spike them especially the c boards. I killed a samsung panel once spiking those c boards or the samsung equivalent of them.

could always check with a meter to see what residual voltage may be still stored on the PSU.

I've never done any electronics repair... most I've ever done is built a PC. I think I understand all this and will try tonight and see what happens. I do have a meter, not sure exactly what to do with it.

And yes the LED light on the front of the TV flashes 1 time red on a constant basis. If I hold Power button it then does 10 flashes

[mpj31]

Re: Panasonic TC-P42GT25

Well I got it open. What is next?

https://www.dropbox.com/s/dwvhb7807j...2016.22.34.jpg

[tw2005]

Re: Panasonic TC-P42GT25

Well, might as well see if it's a genuine 1 blink. I was giving it a bit more thought, chances are it is but try this anyway.

I'm a little unsure about the layout of this model , 2D or 3D?

Does it have just the following boards, SC,SD,SU,PSU,SS, C1,C2 and A-board?


If so, try

Disconnect,

power at SC2 which in the photo it looks like you have.
power at SS11
At the PSU disconnect P35 , this feeds the C boards at the bottom of the panel.
disconnect the three white ribbons at the A-board.


Power up and see if 1 blink still.

Avoid reconnecting the cables straight away as there will be voltage still present from the PSU, you don't want to spike the c boards, can blow the panel, I have on an old samsung.

A multimeter would be handy to measure any residual voltages, about 200v at the Sc/SS boards SC2/SS11

I have had an A board which had a sos1 due to corrupted eeprom on yours it would be IC9304 which you can order programmed but I have no way of proving that would be it or not.

The other common fault is the SC board shorts at SC2, shorts the PSU and you get SOS4, but I've read SOS10, maybe SOS2, 6 & 7.

[mpj31]

Re: Panasonic TC-P42GT25

ill Try What you Recommended And Get Back To You. I Will Comment That I Plugged Sc2 Back In And Booted Up Tv TO Make SUre I Could See Lcd Blinking And I Got SOS4 Instead Of 1.



On My Phone, Hence The Odd capitalization Of Text.

[mpj31]

Re: Panasonic TC-P42GT25

Ok well I did what you told me by disconnecting everything and we have something to report at least. Not sure what you were looking for, but I ended up getting a steady red LED. What should I try next?

https://www.dropbox.com/s/ssyaxpt4x3...2013.16.22.jpg

[tw2005]

Re: Panasonic TC-P42GT25

Ok, The sos4 you reported is the key I believe, check resistance across SC2 and report back, expecting zero ohms or very low.

The sos4 suggests shorted PSU, usually it's the SC board.

The fact the led went normal with everthing disconnected from the A board proves the A board is good.

[mpj31]

Re: Panasonic TC-P42GT25

Ok I plug everything back in that you had me unplug earlier. Then you want me to test resistance of SC2 while the TV is plugged in and turned on?

I have a multimeter... where does the red end go and where does the black end go. Sorry, learning here...

Edit:

Ok so without turning the TV on and everything still disconnected I did as follows and touched the two metal parts. Shown in pic below is somewhat what I did although the red is not touching in my picture.

I get a reading of 193.~ on the multimeter set to 200 setting.

https://www.dropbox.com/s/f5e9cj30km...2017.40.19.jpg


I see another thread here:

https://www.badcaps.net/forum/showthread.php?t=30351

It looks like they actually removed the board and tested underneath... I'm trying to avoid having to remove anything at this time...



Edit 2:
From another one of your posts you posted a link to a troubleshooting guide. I was skimming through it and tested resistance of VFG and VFO and only get about 81K instead of recommended 190K. I tested VFG and 5V_F and indeed got 2.6K as recommended.

[tw2005]

Re: Panasonic TC-P42GT25

With TV off, SC2 disconnected, measure resistance across the pins on the SC board at SC2 or set to diode mode / continuity . Continuous beep or low ohms or 0 ohms will be bad.


I don't know what you are telling me with 193. resistance or voltage.

I you could give me the part numbers and version of the SC/SM boards. usually a white sticker on the boards or could be a two letter siffix stamped . eg TNPA5081AH , TNPA5086AC ?

I forgot the 42" have combined SU/SD, only touched the 50" versions

Also a full photo of the layout of all the boards in one shot.

You can attach photos, go advanced, manage attachments, upload the file.

Max res is 2000 x 2000,

[mpj31]

Re: Panasonic TC-P42GT25

Hopefully you dont mind me linking to my dropbox so I don't have to readjust the pictures. Here are some high-res shots.

Again when I test resistance as you described with TV off, with the multimeter in the position shown in picture 2, I get a reading of around 193.~.

To confirm what you probably already know this is a 42 inch 3d television purchased around Sep 2010. Lot of money spent on this to see it die in 3 years.

https://dl.dropboxusercontent.com/u/...2/TV%20001.JPG

https://dl.dropboxusercontent.com/u/...2/TV%20002.JPG

[tw2005]

Re: Panasonic TC-P42GT25

Well i don't know much about 3D, interesting there appears to be no extra boards from the standard 2D or at least i can't see any.

So I can't see the meter in the shot but if it's 193 ohms that would be bad although usually they go pretty much short cct.

Generally you can see around 300k ohms at that point or if you measure it and remove the leads then put them on again straight away it can switch to measuring Meg ohms. Swapping the leads across can give different results. what ranges do you have to chose on the meter?

If you power up without the Sc2 connected, does 4 blink go and you have 6 or 7 blinks?

[mpj31]

Re: Panasonic TC-P42GT25

You want me to connect everything except SC2 and give it a shot?

[tw2005]

Re: Panasonic TC-P42GT25

yes, hopefully no sos4 but i think it will be sos7

[mpj31]

Re: Panasonic TC-P42GT25

Yes, sos7 is what I got, assuming I got the ribbons back in correctly. my meter goes 200 to 2000k

[tw2005]

Re: Panasonic TC-P42GT25

Ok, I know we may seem to be going in circles but reconnect the Sc2 to re confirm the SOS4, hopefully. I'm quite confident the Sc is bad just a little surprised it's not dead short , 193 ohms is way too low, you could set the meter to a higher range and reconfirm 193ohms, I don't know the quality of the meter you have.

as for those resistances for VFo etc, I'll need more info on where and how you measured those whether we're talking at the Sc or the Sm or at the SC withthe Sm connected etc.

Do you know what guide you used?

I had a quick look at another model with a SM and the pinouts for the buffer resistance tests appear to be different to the SD/SU setup.

You'll have to test the buffer resistances too before replacing the Sc just in case they have shorted too. In most cases it appears they survive but not always and I have been caught out being lazy on this and blown up a new SC much to my disgust on a 50"

[mpj31]

Re: Panasonic TC-P42GT25

The guide I used was posted by you in another thread back in July or so. I can't seem to locate it anymore. It said to do a few things and I said "Hey, that looks like mine on the same board, so lets see what happens". It then proceeded to say to unscrew some things and I did not go as far as that yet.

As far as reconnecting SC2...

Without it connected I get about 314 on a 2000 setting, 192 again on a 200 setting.

Upon reconnecting SC2 I'm back to SOS1, not 4. I'm not sure why I saw 4 at one time...