Panasonic Viera P42U10E Replacing buffer board! What to check?

[Moreno83]

Hey guys ,

Im having some trouble with this TV. It has a shorted lower bufferboard. Upper board is fine and SC board is also fine. ( did the jumper check and tv stays on ).

I replaced the buffer board before and forgot to test it and same issue , tv is blinking and board is short.
I now have a NEW lower bufferboard ( TNPA4785 ) which i want to replace in the tv , what can i do to prevent the board to get shorted to? I tested the new board and it has NO shorts!

Are there any tests that i can do? Is the panel shorting the board or the SV board shorting the buffer board?

[Moreno83]

Re: Panasonic Viera P42U10E Replacing buffer board! What to check?

Vsus on sticker is 209V , im measuring also 209V.
I measured the 4 " iron blocks " ( ZA411 ) where the screws go into and it measured " - 130V ".


TPVSUS = 208.9v ( ground to test point ).
TPVSET = 290.8v ( ground to test point )
TPVAD = -217.2v ( ground to test point )
TPVSCN = -60v ( ground to test point ).


Im afraid to place the new board , don't want to brake it!

[Moreno83]

Re: Panasonic Viera P42U10E Replacing buffer board! What to check?

From the service manual :

Vset
TPVSET (SC) = 290V ± 9V

Vad
TPVAD (SC) = - 195V ± 2V
VR16600 (SC)

TPVSCN (SC)
Vad_base : 148V ± 1V GND_base : - 47V ± 3V
VR16841 (SC)

Vda
TP9 (P)
60V + 1V, - 2V

[Moreno83]

Re: Panasonic Viera P42U10E Replacing buffer board! What to check?

This tv won't turn on with just the upper buffer board only , still 7 blinks. Is that normal for this set? I read that some panasonic plasma's work with just 1 buffer.

Also , TPVAD is around -217V on my set and in the manual it says it has to be around -195V. I tried to alter the voltage with the correct pot meter as shown in the manual but it won't drop to -195. It just stays on -210/217. Is that because the buffer boards are not connected? Btw , all voltages are without the bufferboards connected.
Test point 9 on the PS is 60V so everything looks good but im afraid that if i install both bufferboards that i get the 7 blink code again due to a bad panel. Panel and tabs all look good.

I hope that someone can verify that my voltages are ok and that i just need to install the boards to see if it works or not........

Sorry for all the info , just want to be sure and not break the board!

[Moreno83]

Re: Panasonic Viera P42U10E Replacing buffer board! What to check?

I corrected all the voltages including VAD and installed the NEW buffer board.

7 blinks and the new board is short. This tv is going to the trash.......