Visio VP422-HDTV10A Sound but no picture.

[lookimback]

I got this as a trade in on for a TV I sold last week. I have all the correct voltages coming from the power supply. I even tried a known good power supply just to rule that out. The service manual is worthless for this TV. As I said in the title, I have sound. So I guess it comes down to the X and Y mains, and the Y buffer. How can I determine which it is?

[lookimback]

Re: Visio VP422-HDTV10A Sound but no picture.

I might have figured it out. I pulled and tested all the MOSFETs from the X and Y mains. I found this one, which only stays on for about ten seconds, on the Y-main. It's Q5006 and it says YFR next to it. Not sure what that means.

[lookimback]

Re: Visio VP422-HDTV10A Sound but no picture.

Fixed! It was the X and Y sustain boards. I Also bought a Y-buffer, which didn't work. I'm stuck with that because It's been too long. I may try to fix it someday, but this TV has a buyer already so it will have to wait. Is there a way to isolate which IC is bad on them? I see there's jumpers soldered on it. What happens if you remove them?

[lookimback]

Re: Visio VP422-HDTV10A Sound but no picture.

I had to take this back part. I'd forgot about the need to check and adjust the voltages. Picture was a little off, slightly fuzzy. Vs was 206.3v, Ve was 94v. I adjusted them to 207 and 95, respectively, as indicated on the panel sticker. Now the picture is quite sharp. It's really surprising how much difference is made by 1 volt. Va was also off, 54.56v, rather than 54, as indicated on the panel sticker. I wasn't able to find a potentiometer for it though.