Please help me fix my beloved Panasonic TC-P65ST30

[Davi.p]

Re: Please help me fix my beloved Panasonic TC-P65ST30

to test the drain pin you can solder to the solder side a long wire or you can simply trace where the drain pin is connected to an exposed pin of someone else component, usually the transformer pin, or better a diode bridge pin (check continuity beteween mosfet and it first)

[Ren01]

Re: Please help me fix my beloved Panasonic TC-P65ST30

to test the drain pin you can solder to the solder side a long wire or you can simply trace where the drain pin is connected to an exposed pin of someone else component, usually the transformer pin, or better a diode bridge pin (check continuity beteween mosfet and it first)

Thank you for that tip! Using one probe on on the leg of d412 which is shorted with the drain and another probe on the heat sink I’m getting 0 volts DC or AC. Similarly, the source is also 0 volts.

Would this mean the issue is the mosfet isn’t being fed VCC?

[Ren01]

Re: Please help me fix my beloved Panasonic TC-P65ST30

I traced VCC back to these components, do they look bad? In circuit d407 is measuring very high resistance both ways. D404 measures around 200 ohms one way and very high the other. I also can’t read the labels at all.

[Ren01]

Re: Please help me fix my beloved Panasonic TC-P65ST30

Just a side note, VCC is at 0 volts, and I have confirmed there is 120 volts going to the main power board.

It seems the transformer connected to VCC is also putting out 0 volts :/

[Ren01]

Re: Please help me fix my beloved Panasonic TC-P65ST30

The transformer is also not receiving any voltage on the other side, and that seems to be connected to a relay on another board that I cannot tell if it is faulty. This is going over my head.

[Ren01]

Re: Please help me fix my beloved Panasonic TC-P65ST30

Just a side note, VCC is at 0 volts, and I have confirmed there is 120 volts going to the main power board.

It seems the transformer connected to VCC is also putting out 0 volts :/

VCC is seeing 143 ohms between it and source pin, but only in one direction so I'm guessing diode.

[Davi.p]

Re: Please help me fix my beloved Panasonic TC-P65ST30

test in volt the diodes D201A / D202A under heatsink, both pins.. them are on the primary side

[Ren01]

Re: Please help me fix my beloved Panasonic TC-P65ST30

Plot twist, I ordered a replacement board from TV Parts today and the TV still won’t turn on! New board is exhibiting same issues and I’m stumped!

[budwich]

Re: Please help me fix my beloved Panasonic TC-P65ST30

this thread might help you a bit... https://www.badcaps.net/forum/showth...t=panasonic+sm
There is a tech guide therein which might give you some help.

IF the replacement board is good (was good) and there was no changed, that would suggest that you are looking in the wrong place for the root cause.

Based on a quick peek at the guide, it appears that some form of standby voltage should exist. That is fed to the control board which then can do "stuff" to cause tv functions thereafter.

Actually, one question is: which board did you replace?

[Davi.p]

Re: Please help me fix my beloved Panasonic TC-P65ST30

The same old boring board swap... sadly it is hard to improve knowledge by forum use...
Unless you don't buy the entire power boards kit it is nonsense..

[Ren01]

Re: Please help me fix my beloved Panasonic TC-P65ST30

Just a PSA, that I did end up fixing my TV, but DO NOT BUY parts from TV Parts Today or www.tvpartstoday.com . They sold me a defective PSU board and it took me an extra month of troubleshooting and buying additional parts to figure this out. Pay more and buy from a competitor that actually tests their boards before sending them out.

Thanks again Davi.p for all the help!

[Davi.p]

Re: Please help me fix my beloved Panasonic TC-P65ST30

bye..