Sony Bravia no picture but backlight on

[capxrf]

Re: Sony Bravia no picture but backlight on

Alright then. Thank you all very much for all your help and patience. Hopefully soon i will find replacement boards. When/if I do, I will post the results.

[tmwalsh]

Re: Sony Bravia no picture but backlight on

FWIW, I did a google for the y32... board, and got 571 hits ... some being sold for $49.95. Of course that particular site has it listed elsewhere for more when used in a different model set, and a different price. Zero in stock.
Apparently it fails as there were ~276 stocked at moduslinkptstvboards.com

tom

[bobbyvalentino1978]

Re: Sony Bravia no picture but backlight on

I have a similar problem. Picked up a 46" bravia (kdl-46w3000) for fairly cheap. doesn't turn on but stand by blinks 5 times, stops, 5 times, etc.
I have been told to replace the T-con board...
Problem is that I am a hardcore newbie. Where is the T-Con board? see picture and please point me in the right direction... P L E A S E!

[Wizard]

Re: Sony Bravia no picture but backlight on

T-CON is staring right at you. Right in middle at top hiding behind the vented cover with 4 little screws.

Do you have multi-meter? Take T-CON cover off and find a small SMD fuse and measure this first, tend to be very near the LVDS connector. You want very low ohms. If high ohms, bridge this old fuse with 2A picofuse secured with bit of soldering job on both ends. Take very clear picture of the exposed T-CON board.

Make sure T-CON have thermal pad atop the big square chip and any smaller ones if are there.

Cheers, Wizard

[bobbyvalentino1978]

Re: Sony Bravia no picture but backlight on

Hi Wizard, thanks for the info.
So i removed it and am posting a few pics just in case other people have the same problem with the same model tv.
This first picture is of the Fuse that you mentioned. I will test and will post outcome.


However, it appears that the thermal pad was not placed properly.
This picture shows how the thermal pad was placed.


Is this where it should go instead?

[Wizard]

Re: Sony Bravia no picture but backlight on

Thermal pad is in correct spot for the switching voltage regulators.

The IC does not have thermal contact with circuit board. What I would do is add another pad to TOP of the square IC package and use the cover as heatsink when you source a good board.

Cheers, Wizard

[bobbyvalentino1978]

Re: Sony Bravia no picture but backlight on

If I can't fix this board, where can I order one online?

[bobbyvalentino1978]

Re: Sony Bravia no picture but backlight on

Ok - so here is where I am now.
I took the board to an electronic parts place to look for a replacement fuse (LF 3A). The guy said he didn't have the exact one but sold be something that would do. See picture for a better visual.
Upon installing it, the tv screen went on for about 5 seconds, then turned off and started the 5 blink code again...
I can easily replace the fuse again but it will probably burn again.
What is causing it to burn?

[bobbyvalentino1978]

Re: Sony Bravia no picture but backlight on

Ok - so here is where I am now.
I took the board to an electronic parts place to look for a replacement fuse (LF 3A). The guy said he didn't have the exact one but sold be something that would do. See picture for a better visual.
Upon installing it, the tv screen went on for about 5 seconds, then turned off and started the 5 blink code again...
I can easily replace the fuse again but it will probably burn again.
What is causing it to burn?

Or should I just just follow Wizard's first advice of using a 2A picofuse...?

[kc8adu]

Re: Sony Bravia no picture but backlight on

what is the value on the original and the one you installed?
cant read them in your pictures.
since it played maybe you underfused it?
btw in all the fuses i have replaced like that i have never seen a repeat blow.

[PlainBill]

Re: Sony Bravia no picture but backlight on

Ok - so here is where I am now.
I took the board to an electronic parts place to look for a replacement fuse (LF 3A). The guy said he didn't have the exact one but sold be something that would do. See picture for a better visual.
Upon installing it, the tv screen went on for about 5 seconds, then turned off and started the 5 blink code again...
I can easily replace the fuse again but it will probably burn again.
What is causing it to burn?

If the replacement fuse was rated for less current than the original, that's the problem. I would not recommend trying one rated for MORE current than the original.

If the replacement has the same current rating, something is drawing too much current. The logical place to look first is the power converter in the upper right corner of the board. IIRC, Wizard has mentioned the high speed diodes as a possible culprit in supplies like this. If I were working on this, I would try substituting a low resistance (1 ohm or less) for the fuse and look for sources of heat. Maybe Wizard or one of the many other people brighter than me can tell you if that is a good idea.

PlainBill

[bobbyvalentino1978]

Re: Sony Bravia no picture but backlight on

the original fuse was a LF3A...
Wizard, what do you think of Plainbill's feedback?

[Wizard]

Re: Sony Bravia no picture but backlight on

3A

And I think you have a bad ceramic SMD on voltage supply somewhere. Start measuring with your ohm-meter and try to find one that is below 80 ohms.

These MLCC big capacitors SMD that is very high density tend to fail by shorting.

Cheers, Wizard

[bobbyvalentino1978]

Re: Sony Bravia no picture but backlight on

newbie question here, but does the power need to be on in order to measure ohms? Am i looking at the ceramic smds only on the t-con board or on all other boards too??

[Wizard]

Re: Sony Bravia no picture but backlight on

unplugged from power for safety sakes!

Yes all these medium to big ones brown-purplish look blocks on T-CON. Rest of other boards don't worry about those yet.

Cheers, Wizard

[bobbyvalentino1978]

Re: Sony Bravia no picture but backlight on

Hi Fellas,

So I borrowed a meter (see picture for the setting I used)
Tested all large and medium ceramic smd. See picture for all measurements.
The ones labelled a through L all measure in excess of 160, except for b (77.8), c (78.1) and L (59.2).
From M through U all seem to be either 4.5 or 2.7, or 2.8.

I feel it, we're close now!!

[PlainBill]

Re: Sony Bravia no picture but backlight on

Hi Fellas,

So I borrowed a meter (see picture for the setting I used)
Tested all large and medium ceramic smd. See picture for all measurements.
The ones labelled a through L all measure in excess of 160, except for b (77.8), c (78.1) and L (59.2).
From M through U all seem to be either 4.5 or 2.7, or 2.8.

I feel it, we're close now!!

Well, you may be feeling the wrong thing. You have the meter on the 200K range. You should have it on the 200 ohm range.

PlainBill

[bobbyvalentino1978]

Re: Sony Bravia no picture but backlight on

Well, you may be feeling the wrong thing. You have the meter on the 200K range. You should have it on the 200 ohm range.

PlainBill

Problem is that nothing happens when I have it on the setting you specified. It stays locked on 1.0

[hardwareguy]

Re: Sony Bravia no picture but backlight on

Wow nice TV....don't give up on it! I have a KDL46XBR2 and love it. I would replace every board in the set if need be to fix mine!

Comparable sets today still cost over $1500.

Check that the Tcon board fuse is the same as the original and put your meter on the 200 ohm scale. Place the leads together on the meter and see what indication it gives you when shorted, it should say 0 ohms or very close to 0 (0.01 or so).

Being familiar with your instrument is vital to your success and safety.

WARNING! NEVER attempt to measure resistance of a live circuit as this will cause a short circuit. You could easily destroy the meter and the circuit you are testing. If the available current is large enough, you could be badly burned. At the very least you'll blow the meter fuse.

DANGER! A meter with a blown fuse may give no indication that it is not working properly. Always test the meter before using it. Touch the meter leads together and make sure the meter reads 0 ohms before using it. If the fuse is blown it will continue to read OL or infinity. This false reading could cause you to assume a live circuit is dead, with consequences that could be fatal!

Follow Wizard's advice...he is THE MAN when it comes to TVs.

[PlainBill]

Re: Sony Bravia no picture but backlight on

Problem is that nothing happens when I have it on the setting you specified. It stays locked on 1.0

That means it is reading more than 200 ohms. 200 ohms is greater than the 80 ohms Wizard mentioned. This means the cap isn't shorted. This is good news, you have eliminated the caps as a possible problem.

And I notice you STILL haven't answered the question - what was the rating of the replacement fuse?

I'm not trying to dump on you, but it's obvious you don't have a strong electronics background. I'm trying to make sure the simple things are correct.

PlainBill