Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

[olegeisler]

Trying to fix this 2010 Panasonic Plasma for a friend . I am an experienced technician, but not so much in plasma TVs, this is just for the fun and challenge.

Hoping for some advice here.

Symptom :

When powering the TV ( power button on the A-board engaged ), a green LED flashes rapidly for a second, the relay clicks - after a second it clicks again -then repeatedly 10 red blinks.

What I have done :

- The F+15V is present P6/pin7 between the clicks of the relay (14.75V )
- The P+15V is present P25/pin1 between the clicks of the relay (15.7V)
- The Vda is present P35/pin1 between the clicks of the relay (60.5V)
- The Vsus is present between the clicks of the relays ( 208V )
- Various SUB voltages on A board OK as long as +15V is present

LED_6V DET on IC1100 on A-board is HIGH
FRC+3.3V DET on IC1100 on A-board is HIGH
MIHO+3.3V DET on IC1100 on A-board is HIGH
SUB+5V DET on IC1100 on A-board is HIGH
SUB3.3V DET on IC1100 on A-board is HIGH

Using the " 2010 - FHD Plasma TV Troubleshooting handbook" i tried :

- Startup without SC20 connected - still 10 red blinks !

Then I purchased a (used) A-board

- Absolutely no change, still 10 red blinks

Other observations (all connectors in place ):

SOS6 from SC board goes HIGH due to Vmid being only 52V ( should be 60-150V as I read it )

SOS8 from SS board goes HIGH due due output being only 29V (TPSS1)

Also tried to dismount D25 LVDS cable, no change.

Now, I have a SS board on the way ( longshot !! )

Any input / advice ?

I could of course have TWO A-boards with the same error - but seems unlikely.

Since the SC/SU/SD boards hav been isolated these should not be at fault - also checked common shorts on SC board - seems fine.....

Yes, I have read the forum ( and half the internet... ) about "10 red blinks" - but most posts seems to relate to older plasmas, with older chassis...

I can of course measure / check anything - any help appreciated and welcomed

[dj01fad]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

Hello there
I had a similar problem with a VT20 TV; this model goes into 10 blinks for more faults than a V og G 20 model. This TV has a D board, so the things are a little more complicated. Probably you have a A-board problem, as I had, and I was running around in circles for a few days. on this TV, if you disconnect the ribbon between the A-board and D-board and start the TV it should start with green led on and display full white image; then you'll have an A-board problem. If not, then you may have another problem, like D-board, or... SC-board or... even SS-board. Les us know what happents. If you already did this test without any change, try another D-board.

[olegeisler]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

Thank you.

I now see I made a typo, it says "Also tried to dismount D25 LVDS cable, no change."

Should be "D5" - just as you suggest. Just tried it again, with both A-boards to be sure, and still 10 red blinks and no white picture with the D5 removed.

Could it still be the D-board, as it is now only connected to the P board, through D25/P25 ?

Checking P25 :

Pin 1 15Vc : Present, 15.8V
Pin 5 STBY5V : Present, 5V
Pin7 S0 : Low
Pin 8 S1 : Low
Pin 9 PANEL Main_ON : 3.3V
Pin 10: SOS4_PS : low

As this is the only way the A-board now can "sense" anything on SS/SC/SU/SD/D boards ( via SOS4_PS - D5 is disconned), I seems left with only A-board or P-board as possible failures, since the 10 red blinks are persistent. Two bad A-boards, with exactly the same behaviour ???

Please correct me if I am wrong !

[Alastair E]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

10 blink with supply, 'VSUS' OK from PSU is 99 times out of 100, the SC Board faulty.
Guess its the infamous TNPA5081....

[olegeisler]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

Thank you

But I tried the following :

Disconnect the SC20 on SC board, and no change, still 10 red bkinks.
This should exclude the SC board ( Slide 53 in attachment ) as I see it.
With SC20 disconnected, there should be no information path to the A-board, which could give the 10 blinks. Please correct me if I am wrong.

I am more and more feeling like i have been cheated on, and actually has TWO bad A-boards.
Found a seller who has a complete kit of boards, I am tempted to buy, even though it would further invalidate the already non-existing economics of this repair.

[Alastair E]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

With SC20 (VSUS to SC Board) disconnected--On a working set--Gives 10-blink because the SC isnt running!

Check ALL the IGBT's on the SC, start with Q661 first...

[olegeisler]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

Ah - see THAT is important information

According to the guide the SC20 disconnect should give 6 blinks !
But if you say 10, I am back on the SC board - YES ! ( Dont believe guides.... I know, I know )

Q661 has no shorts / leaks though.... 60V from C to E with G-E shorted gives no current at all ( <10uA ) - out of circuit...

Other larger semis on board : No shorts / leaks ( in-circuit, low voltage ohm meter )

Hmmmm. OK - so tomorrow evening I will change my focus back on the SC

[Alastair E]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

Remove all buffer board connections from SC inc the screws, short SC50 and run set, making sure buffers dont contact anything--better still remove buffers completely taking care of panel tabs--delicate.

If it runs, there's a buffer issue--but suspect there's summit weird on that SC if there's no shorts...

[olegeisler]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

Thanks again.

Alreay tried that, isolated SD/SU completely ( three connectors + 4 screws and insulating plastic between the boards ) - still 10 blinks

AARRGGHHH!

Well, one more question : On a working set, will D5 / A31 disconnect also give 10 blinks ? ( This should isolate most but A-board as I see it ) - but if it still causes 10 blinks I am as screwed as before.

And, if this is the case, I will jump to find the "weird" issue on the SC - I WILL FIND IT !!!

[martino]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

Alreay tried that, isolated SD/SU completely ( three connectors + 4 screws and insulating plastic between the boards ) - still 10 blinks

Did you short sc50 while trying that?

[olegeisler]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

Did you short sc50 while trying that?

Yes, I did short SC50 - still 10 red blinks. Sorry for not stating that.

[olegeisler]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

Update :

Tried to read a lot of info, focused on the "isolation of A-board" - but some confusion seems to exist, there is obviously some differences between "VT20" and "G20" - even though they are built in very similar ways.

I attached a "technical guide" plus the exact service manual for the TX-P46VT20E.

Following the advice I found, I removed P7 and P6 from the P-board, and shorted 1-3 on P34 - result : Relays click, powers on - the powers down after a few seconds. ( Should produce a running set with black screen )

Also tried the above, but removed D5 - same symptoms as above ( Should produce a running set with white screen )

Green LEDs on SS and SC is lit in both tests as above.
This makes me conclude that the issue is NOT the A-board.

Ordered a D-board on Ebay today......

[Moreno83]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

I know we are talking about a V20/G20 but i know from a fact that the V10 and G10 use the same panels. Only difference is that the V10 uses a extra D board.

SS / SC , PS and mainboard are all the same on the V10/G10.

I managed to get a G10 work in a V10 chassis and other way around. You could find out if the V20 and G20 use the same SC board. If so , you could try a longer SC20 cable and elimate the D board from the tv. You also need other white cables that go to the C boards.

[olegeisler]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

I managed to get a G10 work in a V10 chassis and other way around. You could find out if the V20 and G20 use the same SC board. If so , you could try a longer SC20 cable and elimate the D board from the tv. You also need other white cables that go to the C boards.

OK, thanks for the input. The G20/V20 seems to have the same SC board, yes. For now I will just wait for the SS and D-boards I ordered - will update when I find the cause of this failure !

[dj01fad]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

on a working set, if you disconnect d5/a31, the tv will start with green led on, and full white image. I think D-board is the problem on your TV, but let's wait and see.

[olegeisler]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

Hi All

UPDATE : Received both SS-board and D-board today.

D-board did it, set works ! - so, D-board can actually also cause the 10 red blinks... When BOTH the SS and SC board sends the SOS7 and SOS8, due to lack of drive from D-board, to A-board, it returns the 10 blinks ( shouldnt acoording to the documentation... )

Also tested the A-board 8again ) and the SS-board, both worked. So, at least all boards purchased were OK, and the set is now working

Thanks to everyone.
Will just sell the excess boards again

[vinceroger69]

Re: Panasonic TX-P46VT20E - GPF13DE - 10 red blinks driving me crazy

Thanks for the update glad the new board fixed the issue.