Sony KDL-50W828B sound but no picture

[Joop]

Hello,
I have a Sony KDL-50W828B TV with sound but no picture.
What I eventually did is I disconnected 1 of the lvds ribbon cables between the Tcon and the “buffer boards”. I mean the boards that are connected to the lcd panel itself.

When I disconnect the left ribbon cable nothing happens. Only the backlight stays on.
When I disconnect the right cable, the left of the screen comes on and I have a picture.

I tested all the components on the right buffer board for shorts but I did not find any.
When I measured the voltages on the Tcon to the lvds cable I get a reading of around 1 volt.

With the lvds cable disconnected I get higher voltages around 10 volts.
So it looks like a short on the buffer board or on the right panel itself.


I learned on the internet that if you have the above symptoms the tv is not repairable because there is a fault on the lcd panel.

Is there still a chance that there is a fault on the Tcon?

Thanks for the help in advance.

[yoritomo]

Re: Sony KDL-50W828B sound but no picture

Hello

I had to work sometime on these never models of Sony, and bad news , their LCD panel becomes a crap , I guess if you disassemble the frame of the lcd panel, on extreme right flat ribbon you will find with scare a burnt trace which is not repairable, good enough for the recycle bin . Sad for a success story brand , until now it was only Panasonic and Sony was still right on their shoes, not sure since some years...
Sorry, the short still occurs, i forgot, then it is inside the glass and soon it will burn out with no luck of prevention .

[Joop]

Re: Sony KDL-50W828B sound but no picture

Thanks for your answer.

So this one goes to the landfill. I won't be buying Sony tv's anymore.

[nomoresonys]

Re: Sony KDL-50W828B sound but no picture

If you want to dig deeper there's some good videos on youtube that details test points on the buffer boards and some pretty simple "bypass" fixes that may work depending on the issue.

[nomoresonys]

Re: Sony KDL-50W828B sound but no picture

Some testing there, not in english, has english subtitles: https://www.youtube.com/watch?v=RUlqa1alqH4

[nomoresonys]

Re: Sony KDL-50W828B sound but no picture

Example there but isn't explained in great detail: https://www.youtube.com/watch?v=YacI7hWWKJw

[neilc6]

Re: Sony KDL-50W828B sound but no picture

If there are no shorted chip caps on the bad side, I would try the cutoff tape method on the ribbon connector.

[Joop]

Re: Sony KDL-50W828B sound but no picture

Hi,
I did have a closer look at the lcd and i found a crusty looking trace on the lcd.
It is at the far right bottom corner of the screen. Could that be the short?

Would it be possible to fix this with the cutoff tape methode?
I don't really understand the theory behind this methode. Is it to bypass the bad signals-shorts?

[Joop]

Re: Sony KDL-50W828B sound but no picture

Here's a picture.

[diif]

Re: Sony KDL-50W828B sound but no picture

I'd try giving it a gentle clean with a cotton bud and some isopropanol alcohol (IPA) before playing with tape.

[R_J]

Re: Sony KDL-50W828B sound but no picture

Sure looks like cleaning fluid/water damage, I suspect there is more water damage to the lcd driver board. This happens all the time when people clean the screens with liquid cleaner. That's not Sony's fault

[Joop]

Re: Sony KDL-50W828B sound but no picture

Hi,
Water damage is possible but I did not find any trace of water. Both driver board are very clean and also on the bezel no water stains.

What happened with trace I don't know. Cleaning it is not possible I think because it is behind the glass.

I will have to remove more parts from the bezel to have a closer inspection. It could take awhile because of my limited time.

I will keep you informed.

[Joop]

Re: Sony KDL-50W828B sound but no picture

I am sorry for the late reply.
After some more inspection and testing, even the good side of the screen went bad.
So after that I did not bother to do more testing and I trashed it.

Thanks for your help.

[Hamie]

Re: Sony KDL-50W828B sound but no picture

The tcon and motherboard from these models are quite hightly valued. Hope you didnt just stick it in the trash.