vizio vw42l hdtv10a no picture/sound

[philliesfan30m]

Re: vizio vw42l hdtv10a no picture/sound

do you have pictures of your inverter board or boards? that board or boards i think is known for going bad. you should check the mosfets and driver on that board and see if you have any burn marks and check the mosfets i think they should read 8.5 mohms if not they are bad and the driver might be bad and made the mosfets go bad i think they run in pairs but i am no expert i am just giving suggestions. i had that problem with a vizio v042l but i am waiting for the mosfets to get shipped here

[budm]

Re: vizio vw42l hdtv10a no picture/sound

His board is power supply-inverter board combo.

[philliesfan30m]

Re: vizio vw42l hdtv10a no picture/sound

ok my bad just trying to help but i guess it was bad info. is it me or does it look like in the 3rd pic between the 2nd and 3rd heatsink that those diodes got hot and left a brownish color on the board? i can't zoom in to tell.

[blmcamp]

Re: vizio vw42l hdtv10a no picture/sound

Sorry again I had to go to Disneyland with my family for 5 days. hope I still can get some help. I took some close up pictures of the are mentioned in the post above. I don't think that the board appears to have been overheated. I hope you can tell from the photos. It looks worse in the picture than in real life. also I had the board off and the back side of it does not appear to be discolored at all. I was also wondering about the blue led light on the board above the power board, sorry don't know what it is called. when I press the power button the blue light comes on bright and them dims after a few seconds is that normal?
I sure appreciate your patience and assistance.

[budm]

Re: vizio vw42l hdtv10a no picture/sound

OK, put the meter in DC 400v RANGE, TV plugged in, measure the dc voltage right at the two legs of that large brown filter cap laying on its side, it should read about 160~170VDC, the hit the power switch, then it will go up to around 380~400VDC. You will be working in the Primary (HOT DEADLY SIDE) so do not touch anything with your hands.

[blmcamp]

Re: vizio vw42l hdtv10a no picture/sound

bud
I was careful and took the readings you asked for.
I think the filter you are talking is the one on the power board on the left hand side near the power input.

If I put the positive lead on the right hand side and the common lead on the left hand side I get the following readings
power applied, power switch off, front "Vizio" Light amber = 160vdc
power applied, power switch on, front "Vizio" light white = 370

Note: I am using a craftsman analog multimeter 82362 and am interpreting it as best as I can see it so the readings may not be as on accurate as a digital multimeter.

[blmcamp]

Re: vizio vw42l hdtv10a no picture/sound

Been a couple of days and I was just want to let ya know I am still interested in getting this TV fixed.

[budm]

Re: vizio vw42l hdtv10a no picture/sound

OK the PS_ON is OK because the DC voltage did get boosted up to 370VDC. We need to look at the Inverter circuit section next. To do in depth troubleshooting down to component level, I will need really good clear focused pictures of the whole top side and whole bottom side of the power supply board, then small closed up pictures of the bottom side in small sections.

[blmcamp]

Re: vizio vw42l hdtv10a no picture/sound

I will take those and send them right now

[blmcamp]

Re: vizio vw42l hdtv10a no picture/sound

Ok, There are a lot of them but here they are.
I have asked this before, I know, But is the blue Led light on the board above the power/Inverter board suppose to turn blue and then dim out when we push the power on button?

[blmcamp]

Re: vizio vw42l hdtv10a no picture/sound

and more

[blmcamp]

Re: vizio vw42l hdtv10a no picture/sound

and still more

[johnboy1313]

Re: vizio vw42l hdtv10a no picture/sound

But is the blue Led light on the board above the power/Inverter board suppose to turn blue and then dim out when we push the power on button?

Yes, I just fixed this exact TV on Saturday. No picture, good backlights. It turned out to be U7, U33, and U9 on the main board. U7 and U33 are adjustable 1117 voltage regulators. U9 is a 1117-15, 1.5V regulator.

[blmcamp]

Re: vizio vw42l hdtv10a no picture/sound

well. Ok, I may be able to replace U7 or U9 but if it is U33 then I will have to buy a new main board.
I attached some photos. are these the ones your are talking about?
will you please tell me how to test them to see if they are bad.
Thank you

[johnboy1313]

Re: vizio vw42l hdtv10a no picture/sound

You must have a different main board than I did. U7 looks right, U33 looked exactly like it and was the first regulator to the right of U7. U9 was the first regulator below U7. They all look similar.

What's you main board number?

[budm]

Re: vizio vw42l hdtv10a no picture/sound

"No picture, good backlights" but you do not have backlights, his (John) does have backlights but no pictures.

[johnboy1313]

Re: vizio vw42l hdtv10a no picture/sound

I got blmcamp and Echo210 miced up. Sorry about that.

[budm]

Re: vizio vw42l hdtv10a no picture/sound

I am still looking through those pictures to draw up the diagram.

[blmcamp]

Re: vizio vw42l hdtv10a no picture/sound

Thank you.
I sure hope I can get this fixed for them.

[budm]

Re: vizio vw42l hdtv10a no picture/sound

Sorry, still do not have time yet. Will try to do it this weekend.