Vizio VP50 HDTV20A power supply turns on then off

[chouston]

I have a Vizio VP50 HDTV20A which I recently got from a customer, he claimed it made a loud pop and stopped working, I hauled it off, opened it up, saw two blown 10v 3300mf caps, replaced them and plugged it back in. It clicked when I plugged it in then when i hit power it clicked once, then again, the orange led on front turned green but that was the end of it. I hooked up my meter to the back and watched the power outputs from the PS board jump up to the labeled voltage when I hit the power button, then immediately after the second click, drop back down to zero. No fuses are blown and I don't see any other bad caps anywhere... Any suggestions are greatly appreciated...

[rayrod81]

Re: Vizio VP50 HDTV20A power supply turns on then off

One of the sustain boards is most likely causing the power supply to shut down. These boards have a history of failing on this panel. Check all of the mosfets on the Y and X board for shorts.

[chouston]

Re: Vizio VP50 HDTV20A power supply turns on then off

I looked at both the X and Y boards and cannot find anything identified with a Q to identify a mosfet...

[rayrod81]

Re: Vizio VP50 HDTV20A power supply turns on then off

There are at least 10 of them on each board if this is a Samsung panel. Post pictures of the back of the TV and the individual boards. Use manage attachments and do not post them inline. This could be an LG panel but that is a whole different animal. So post pictures and that should give us a better chance to help you.

[chouston]

Re: Vizio VP50 HDTV20A power supply turns on then off

Thanks, I will take pictures when I get home, however I am fairly sure it IS a LG panel. I read other posts of folks having similar problems and all their pictures looked different from the boards in my tv. Also, the smallest board inside, which contains 4 surface mounted lcds, has a LG chip on it. But again, I will post pictures when I get home.

[rayrod81]

Re: Vizio VP50 HDTV20A power supply turns on then off

Sounds like the 50X4 panel in this one. If that is the case,then most likely the Y or Z sustain has a short on one of the IPMs causing the PS to shut down.

[dejesus]

Re: Vizio VP50 HDTV20A power supply turns on then off

what is IPMs? i have the same tv with the same problem.

[tom66]

Re: Vizio VP50 HDTV20A power supply turns on then off

IPMs are the large devices under the large heatsinks on each sustain board.