Sony Bravia no picture but backlight on

[capxrf]

Re: Sony Bravia no picture but backlight on

Here are the pictures

The first is of the back of the tv with all boards uncovered

second is the main board

third is a closer view of main board

fourth is the inverter board

fifth is the power supply

and last is the little board at the top of the tv between main board and LCD screen

[capxrf]

Re: Sony Bravia no picture but backlight on

Well, since the backlight is looking good and bright, would the inverter board even be an issue? All it does is backlighting right?

It's gonna take a while for photos to load up for me, but they're on their way

[infringer]

Re: Sony Bravia no picture but backlight on

Wow stj that is good information to know thanks a million man makes perfect since to me. Great tip.

[stj]

Re: Sony Bravia no picture but backlight on

oh yea, there was a sony alert to repair centers about some large bravia's
if you have a long board at the side with loads of invertor transformers on it, and it has a plastic cover over it - take the cover off.
it traps the heat and causes faults!

[PlainBill]

Re: Sony Bravia no picture but backlight on

I've said this repeatedly to others, now it's your turn. Attach good quality pictures of the boards to your next post.

PlainBill

[infringer]

Re: Sony Bravia no picture but backlight on

Look for chip id's with a magnifier look those ID's up ... You will find out what there functions are voltage regulators if you google that what does that bring up for you to me a complete newb anything that regulates voltage is a voltage regulator... So I see where you would be lost as well...

But I remember chips that show LMXXX as being voltage regulators this may be what you are looking for as well...

http://www.national.com/cat/index.cgi?i=i//75

This may help you a little bit...

[capxrf]

Re: Sony Bravia no picture but backlight on

Alright, I guess I need more help than i even thought. I can't find the service manual/schematics for the tv either. I found one for a model KDL-32L4000 and KDL-37L4000. The boards look the same visually, but the manual isn't for my model

[capxrf]

Re: Sony Bravia no picture but backlight on

Thats where you lose me a little. What am i looking for in the way of voltage regulators? everything is tiny on the main board. Am i looking for a chip? I've been searching for schematics. I'm having a time locating any

[stj]

Re: Sony Bravia no picture but backlight on

download the schem's if you can find them - some are around.

look for voltage regulators on the scaler/processing panel & check there outputs.

[capxrf]

Re: Sony Bravia no picture but backlight on

Alright, I was more thourough today and tested the power supply again. All output wires are correct, (the two pins labeled pwr_panel tested at about 3.5v, I assume this is correct as everything else is and the two pins are identical) and the supply grounds are good. Still have 50 some volts over those three heatsinks, but i ust don't touch them, and they are obviously designed that way

So now I'm stuck again. Anyone have any experience with this?

[capxrf]

Hello, I'm new to posting, but not at all new to reading here. Thank you all for all your past help you didn't know you gave!

I just bought a really cheap Sony Bravia TV with no picture for myself to fix. I have a good deal of electronic repair experience, and have been doing a lot lately, so I figured this would be relatively simple, but no go, so here's the deal.

It's a 32” (31.5” diagonally) Sony model KDL32s5100. The tv turns on fine. Green power light comes on solid and stays on. Backlights are bright. Unit is in great condition and hardly used it appears. Not tampered with.

No picture though. No menu, nothing but backlit screen (screen is perfect). I can change the brightness with a combination of button pushes, so I can assume the menu is working, just I cant see the graphics.

No bulged electrolytic caps. Touched up any iffy solder on power supply (no change). No cracks. All wire connections there. All insulators intact.

Two strange things:
1) I read 56 volts from 3 heat sinks on the power supply to ground (hurt to find out) (is this normal? I've never seen it)

2) one pin off the power supply says 30v 2mA on the board, but only tests 17v. (I don't know why, and can't figure how everything can work but the screen if the power supply is bad)

Any suggestions? Where should I be looking? I'm thinking main board, or power supply, but don't know what I'm looking for on the main, and the power is on.

Any help is great, I really want to fix this one.

Thank you !