Jan 15, 2017, 8:45 PM
Post #1 of 2
Hi…been searching all over the place for troubleshooting specific symptoms, without luck. Hoping someone here might have seen something similar. The TV turns on with full functionality, but shuts down after 60-90 seconds, then turns back on…it will cycle on/off until the unit is turned off with remote or unplugged. Which each cycle, the power board relay clicks. The logic board green light blinks about once per second. Oddly, the only time the TV stayed on longer was when I did a firmware update via wireless connection. It appeared to go through full update w/o interruption.
Samsung plasma pn64d7000 cycling on/off every 1 minute or so.
FWIW, I isolated each of the boards and plugged in the TV. Regardless of combination, whenever the main board was attached, the TV would cycle. It would not cycle if main board was disconnected.
Voltage label of Va=55, Vsc=-197, Vs=217, Ve=93
- On power board: Vs=216, Va=55
- On X board: Vs=216, Vb=93 (assuming this is Ve from label)
- On Y board: Vsch=-39, Vscan=-197
I had a Geek Squad tech come to the house for a diagnostic. $100 later, I was told the Y board was defective, and that he broke the top off the Vscan adjustment knob (left it with Vscan=-181). A new Y board would be $320 plus labor. He thought main and power boards were sound.
So I purchased a used Y board from a well, known auction site. After install, there was no picture at all and a noticeable humming noise. Put the original board back in TV and it resumed its on/off cycling.
Even with top of knob broken off, I managed to adjust Vscan to -197. I could not find info on what value Vsch should be.
All capacitors look ok. ribbons, screws all intact/tight. nothing looks burnt.
I gleaned all this stuff from the web…not really sure I know what I’m doing. Any advice on what tree I should bark up next? Many thanks!
(This post was edited by no_idea on Jan 15, 2017, 8:55 PM)