Sony Bravia no picture but backlight on

[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

[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.

[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...?

[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

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

[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

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

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

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!

[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

[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.

[Wizard]

Re: Sony Bravia no picture but backlight on

Not compatible at all. Had to be *exact*. Sony is odd out.

Spend that money, that Sony is way too good to waste. S5100 series is nice.

Toshiba tend to use normal LCDs.

Cheers, Wizard

[capxrf]

Re: Sony Bravia no picture but backlight on

Dang. Well then, I'll do some searching for another for a bit.

I do have a "32 Toshiba Regza with a smashed screen. The T-CON boards on them look different, but just to check... this other tv couldn't help me any could it?

[Wizard]

Re: Sony Bravia no picture but backlight on

Cannot do. Only way is get a T-CON and try. If not, you can stilll hold on it and get another one or sell the TV in pieces on ebay.

Cheers, Wizard

[capxrf]

Re: Sony Bravia no picture but backlight on

Is there a way to determine which is the issue first? $50 would be worth it, but not if I found later that the screen was gone too (can't afford that for a free tv).

[Wizard]

Re: Sony Bravia no picture but backlight on

This means mainboard is fine. Either replace the T-CON, but make sure you have voltage on that fuse. Failing that, LCD panel itself.

T-CON on used market is usually 50-120 dollars. Panel is around 800-1,500 in that size.

Cheers, Wizard

[capxrf]

Re: Sony Bravia no picture but backlight on

oh, well then yes, I can indeed get audio from Component #1 with the television. I can't seem to make the audio switch to the other sources though with the "input" button.

[Wizard]

Re: Sony Bravia no picture but backlight on

Use the source that you can plug to the TV. composite, component with audio cables or composite even s-video with audio cables.

Trying to blindly tune to a channel is harder.

Cheers, Wizard

[capxrf]

Re: Sony Bravia no picture but backlight on

Yes, I had already checked the fuse on the T-CON board (thank you for the new name). It tests positive for continuity. You said to "Blindly change to a video input with video and audio attached". The only connection like that I can think of is HDMI or the coaxial, am I correct? I'll have to find someone with an HDMI output device since I can't see anything to set up with my converter box... I'll get on that soon hopefully.

[Wizard]

Re: Sony Bravia no picture but backlight on

Blindly change to a video input with video and audio attached. If you get audio, that means TV is fine and whole LCD panel is probably good, that why I suggest check fuse on T-CON board, fuse is small and usually marked with a one letter and is very close to the LVDS connector. This can fail. That last picture is called T-CON (timing control). If fuse is still good, see if you can get one from sony or ebay or google may find one.

That one is a square cross section fuse with metal square end caps and it does have a number marked on white body. Fuse is just above the LVDS connector to the left. They sometimes fail for no reason. Changing fuse or solder a picofuse over the old fuse is sufficient.

Cheers, Wizard