Riddled TV Repair Forum

Tjp444 · Joined: 18 Sep 2009 Posts: 5 Location: Indiana

I'm working on a Vizio 42" plasma VP422, the previous owner said it went dead, he took the back off and in the process put a crack in the glass so he gave it to me.

The panel is OK and I **think** the power supply is OK, the supply voltages are all within spec. Here's the puzzle: I can have any three buffers attached to the screen at a time and those parts of the screen look fine. As I add buffers (unplugging the set each time), vscan on the Y-main keeps dropping and the picture gets worse and worse. I checked the ESR of all the caps on the supply and replaced one on each board (supply and Y-main) for being suspect but not way out. I checked the semiconductors on the y-main, replaced one shorted diode (not a heat sinked one), before I replaced that there was no vscan at all.

So, is it the power supply not supplying enough current, bring the vscan down under load, or is it the y-main failing in some undetermined way?

Thanks for your thoughts on this.....

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