Vizio VX37L backlight not coming on

[tom66]

Re: Vizio VX37L backlight not coming on

3.11V is too low though for 3.3V regulators. If the main board crashes it may turn off the 24V, but I'm not sure about the 12V. Ideally you would fix the regulators first so a baseline of correct main board operation can be established.

[aaronwt6]

Re: Vizio VX37L backlight not coming on

Sounds good. I'll get these ordered and go from there.

Update to come!

[tom66]

Re: Vizio VX37L backlight not coming on

Are you now getting 3.33V on regulators?
I thought you had 3.11V but you've edited the post?
Because 3.33V is fine, we would need to look elsewhere...

[aaronwt6]

Re: Vizio VX37L backlight not coming on

U16 seems to be the only low one. That's why I said check the edit. Sorry again about that.

[tom66]

Re: Vizio VX37L backlight not coming on

U16 is fine; -25 = 2.5V output.

[aaronwt6]

Re: Vizio VX37L backlight not coming on

Ah, ok. I've got to go pick up dinner for the family but I'll move on to the next step in a bit. Not sure if you saw above in the thread but I unhooked the control board completely yesterday and still could not get the voltages on the supply to hold steady when I power it up.

I did that by putting a jumper from the STBY to PSON. Not sure if that's the correct way to go about it but it seemed to work.

[aaronwt6]

Re: Vizio VX37L backlight not coming on

It's funny Tom. Electrical engineering degree and I swear I never knew what those numbers on the regulators stood for.

[aaronwt6]

Re: Vizio VX37L backlight not coming on

Just a note I had mentioned U1 earlier which is a 7805 on the control board. Pretty sure it's part of the 12v circuit which explains why I have nothing on that one at all.

[budm]

Re: Vizio VX37L backlight not coming on

12v and 24v are generated by the same power transformer. So if you use 1k resistor between the PS_ON and the 5V STBY pin, then you should see the 12v and the 24v come on.

[aaronwt6]

Re: Vizio VX37L backlight not coming on

Thanks budm. I'll give this a try tonight after work.

[aaronwt6]

Re: Vizio VX37L backlight not coming on

Ok. Tried that and the 12V is still missing and the 24V acts the same as before. Starts our around 14V and drops to 1-2V quickly. I'll have to get back to this one sometime next week.

[aaronwt6]

Re: Vizio VX37L backlight not coming on

Got this one going. Just swapped the whole supply. $25 for it on Ebay shipped. I may look at the old one later.

Thanks as always for the help everyone!

[tom66]

Re: Vizio VX37L backlight not coming on

Glad to hear it's going now.

[aaronwt6]

Re: Vizio VX37L backlight not coming on

Definitely need to get down to the component level repair. This hobby is highly addictive.

[tom66]

Re: Vizio VX37L backlight not coming on

You betcha. I just keep looking everywhere for discarded faulty TVs to fix.

[aaronwt6]

Re: Vizio VX37L backlight not coming on

No doubt. I find myself scouring craigslist every day now. I'm buying things I don't need to to fix em.

[tom66]

Re: Vizio VX37L backlight not coming on

I have recently decided to keep a lot of the good ones for myself. Two Panasonic plasmas and other TVs too.

[aaronwt6]

Re: Vizio VX37L backlight not coming on

Yes sir. Same here. I keep 'upgrading' us in the house. 50" LG Plasma 1080P is our living room unit.

[aaronwt6]

Re: Vizio VX37L backlight not coming on

Can't understand alot of people's fear of Plasmas. You can't beat the picture and color on a good 600Hz 1080P Plasma.

[tom66]

Re: Vizio VX37L backlight not coming on

Probably based in the old IPM-based LGs... but modern plasmas are a lot easier to repair.