Panasonic TX-P42ST30 with exploding diodes....

[Moreno83]

Re: Panasonic TX-P42ST30 with exploding diodes....

No , black and red prope both on white prong connector. One way it will beep for 1 or 2 seconds. Other way around it won't beep.

A shorted board will beep constant.

[tvtimmy]

Re: Panasonic TX-P42ST30 with exploding diodes....

It will beep for about 2 seconds. Then if you reverse the meter leads it will beep for 2 seconds. If it stops beeping both ways, thats a good start. Dont forget to reflow all the screw hole grounds!

[Moreno83]

Re: Panasonic TX-P42ST30 with exploding diodes....

As Tvtimmy said , both side beep is not good. A good board will beep shortly on 1 side and no beep on the other side. ( black/red propes ).

[satinser]

Re: Panasonic TX-P42ST30 with exploding diodes....

I take it you've tested for short across C842. If present at least one of the buffer chips will be shorted. This I believe also can cause the demise of the trio of SMD diodes D430, D432 and D433. In my case thats exactly what I found buffer chip IC4806 blown and that Grey stuff that Panasonic put around the buffer chips is awful to remove!

[ReeceyBurger123]

Re: Panasonic TX-P42ST30 with exploding diodes....

Our old friend flocko knows a good method of easily removing the buffer silicon on panasonics

[Moreno83]

Re: Panasonic TX-P42ST30 with exploding diodes....

I found a solution for the exploding diodes on a TNPA5330 AB board.

Common failure is that after replacing the 6 FETS ( Q401/402/403/421/422/423 ) the diodes D433/432/430 will explode. The 2 small resistors ( 40K Ohm ) will give a high value or will read short.

The reason is fake parts! I replaced all fets with FGD4536 and replaced the diodes + resistors from a scrap board but it still blew up.
I found out that both DG302 were also short. One is located on Q441 ( Under heatsink and will read short on both legs ) and the other is Q451 which will read short on 1 leg. Well atlas in my case.

I replaced all parts including IC502 + Q531 with original parts and the board is back alive. Watch out that there are fake DG302 / RF1501 / 30F131 and RJP30H2A on ebay!! If the logo is almost gone using nail polish remover then you might have fake part.....

Hope it helps someone.

[matyka]

Re: Panasonic TX-P42ST30 with exploding diodes....

Hi,anyone could help me to fix my tnpa5330 board .I have removed all the shorted Fets .
I have shorted diode near the Buffer IC. See photo
Is this would be normal ? I have measured out the board and are all Ok .