Samsung Plasma PN50C430 Stndby ok, won't power up

[blkrx7]

Hello all, outstanding forum.

I've taken the time to read through the first 50 pages here, but can't find my exact scenario. Hopefully someone has run into this previously.

Samsung plasma, won't turn on. Red LED on the front is solid, no response to the power button.

+5v standby is good, PS-ON (Marked SW_POWER) is 3.3v, but is never pulled down when you hit the power button.

Shorting PS-ON to ground briefly, TV fires up, works fine. Power button works at this point, on/off/on/off. But if you disconnect from the mains, problem repeats.

I suspect the mainboard is responsible here, but can't follow PS-ON pin back to any components to check for a cold solder joint etc. The pad seems to end right at the pin. It looks like a multi layer board, and I can't find any documentation.

Any advice?

TIA,

[tvtimmy]

Re: Samsung Plasma PN50C430 Stndby ok, won't power up

Unplug the ribbon circled in red and short pins 3 and 4 on the same board. Then plug back in. If you get test patterns, the .
Mainboard is bad.