Nov 13, 2017, 9:46 PM
Post #1 of 4
Hi, I'm hoping for some kind help fixing my plasma.
Samsung Plasma (PN58C8000) blank screen.
I've tried to do some debugging based on a "fast track" document I found here: http://www.toms-service-manuals.com/?do=search&mfg=Samsung&modelsrch=pn58c8000&typekey=0&Search=Submit+Query
Then I thought I saw some heat damage on the power board and bought a new one. But that didn't fix my problem.
On power on:
1) Black screen. Red Standby LED flashes 4 times.
2) Cannot display TV Menu.
3) No power on "chime" is heard, but I had the speaker disabled because the TV was downstream of my AVR.
4) Green, LOGIC board LED flashes slowly. About every 5 seconds.
5) STBY 5V is OK.
6) PS_ON transitions from 3.3v to ~124v (instead of 0v) with power on.
7) Vs, Va, Ve, and Vsc all hit their targets briefly then fall away (fast track says this model shuts down power board on problems).
8) Cannot see test patterns when shorting pins on LOGIC board and disconnecting MAIN.
From what I've read, the POWER board behavior when X-main and Y-main are disconnected is often used to decide where to look next. But according to the fast track document, this model's POWER board shuts down when they're disconnected, too. So where do I look next?