Sony KDL-46S5100 Screen Lights Up but No Picture

[Gorrillasnot]

Hello,

Working on a Sony KDL-46S5100 for a friend of mine.

When first plugged in there is no standby light (not sure if this model has one). Press the power button and a light on the bottom turns green and stays lit solid (no error light blinking).
I hear a click from the PSU area, then the back lights come on and the screen lights up like a TV/Monitor would with no signal. Kind of a blue/grayish color.
Pressing the menu or input buttons doesn't do anything.

I checked voltages at the PSU connector and they all seemed correct. 3.3v, 15v, and 12v.
Since the TV powers up and the backlight and screen lights up I am thinking the main board is the likely problem or possibly the Tcon as I can disconnect the cable to the Tcon and the TV lights up just as it did before disconnecting it.

Is there a way to trace it down to the component level or at least which board is bad?
Mainboards for this TV seem a little salty like in the $80-$100 range.
Edit: Mainboard model# is 1-879-020-12

It was kind of dark when I started working on this TV so I will have to wait until tomorrow to get some pictures.

anyways thanks for any info/advise you could give me.

[tom66]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

Try checking the fuse on the T-con board.

[Gorrillasnot]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

I could only find 1 fuse and it reads 0.00 with meter set on 20k ohm. With it set on 200 it reads.0.05.

[tom66]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

Do you have 12V both ends of fuse?

[Gorrillasnot]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

Yep 11.9V on both ends.

[tom66]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

Can you supply a picture of the T-con board?

[Gorrillasnot]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

I'll have to wait until daylight to get pics of my board, but it looks just like the stock photo I uploaded here.

[budm]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

FP1 is the fuse, check and see if you do have 12VDC at both ends of the fuse with ref to the chassis as ground ref point.

[Gorrillasnot]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

FP1 has 11.9V on each end.

I was looking through youtube and came across this video where the guy was working on a Sony with a tab bond problem..Could that be the problem with my TV or do you guys thinks its my T-Con or possibly mainboard?

thanks

Update: Added Pictures

[truep]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

Usually tab bond problems dont cause that symptom, but it's possible. I suspect it's a voltage on the TCON.

[budm]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

Try disconnecting one of the two ribbon cables at a time between the T-CON board and the LCD panel to see what happen.

[audiofreak19]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

I'm curious to find out the problem to this cause I have been troubleshooting a vizio led doing kinda the same thing the backlight lights up but no picture

[Gorrillasnot]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

With the left ribbon unhooked from the T-Con board I briefly saw the Bravia logo on half the screen then it went back to like it was before with no picture, but back lights on.
Tried repeating and the second time I didn't get the Bravia logo. Just the blank screen.

With the right side ribbon cable unplugged I get a picture on the right side of the screen and a brighter plain blue picture on the left.
There also seems to be a dark line going horizontal through the middle of the screen.
I uploaded a pic of the screen with the right side ribbon cable unplugged.

So it's looking like a bad T-Con right?
Can T-Con boards be fixed at the component level or not so much especially for a novice like me?

thanks

[budm]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

You have bad panel, half of the panel is shorted out, that is why when you disconnected the ribbon that feeds into the shorted circuit then it allows the T-CON board to function.

[tibimakai]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

I agree with bud, I had myself this kind of situation, with a 3D Samsung D class TV.

[Gorrillasnot]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

Bummer..it was a nice looking TV..such a waste.

Thanks for ur help everybody

[audiofreak19]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

What if moving the ribbon cables doesn't change anything. U think it would be the t con then?

[Gorrillasnot]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

There's a guy on youtube with allot of good videos on TV repair.
This video shows him doing the test budm recommended I do, on a Vizio TV with similar problems to the TV I'm working on.
He says that out of 100 TVs with a similar problem 98 had a bad panel.

I was going to try a $20 ebay T-Con, but with odds like that I don't think it would be worth it.

Anyways thanks budm, tom66, and everyone else for all your help.

[audiofreak19]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

Yea I just tried it again on mine m550nv and undid the left ribbon and the left side of my screen works and the right side washes out and goes white. I'm soo pissed. I bought the tv for 150 thinking it just needed a main and It did.

[audiofreak19]

Re: Sony KDL-46S5100 Screen Lights Up but No Picture

Question is there wa way to test to make sure a signal is being sent out each of the connectors where the ribbons go. I tried hooking the right connector up to the left ribbon to try and rule out a t con or panel and either way they didn't work