Vizio VF551XVT possible tab bond failure

[angrydingo]

Hello all, i'm trying to troubleshoot a Vizio VF551XVT LED set.

The problem with the set is the right half of the screen is pixelated green and yellow. I can make it go away by gently tapping the side, putting a small amount of pressure, or moving it around slightly on the stand.

Pictures are attached.

I'm thinking it's probably a tab bond failure, but I wanted to get opinions? possible LVDS cable? T-Con?

[angrydingo]

Re: Vizio VF551XVT possible tab bond failure

Bump?

[drussell]

Re: Vizio VF551XVT possible tab bond failure

You're really probably going to have to take it apart and see exactly where you have to bump, squeeze, push, pull, twist or whatever to figure out precisely where the problem is...

It's not really something we can magically tell without the set physically in front of us.

[angrydingo]

Re: Vizio VF551XVT possible tab bond failure

Alright, I think I've located the problem here

It's the 2 ribbon cables in the picture. Jiggle them around and the picture changes, get it just right and the picture is how it should be

Forgive me, I'm sort of new at repairing TV's. I've only done 4 sets and each time, the mainboard was bad!

Are these ribbon cables the LVDS cables? Whats the best way to unseat them, so i can clean and re-seat them? Or are those the cables that lead to the tab bonds on the panel?

Thanks!

[MagicSmoke]

Re: Vizio VF551XVT possible tab bond failure

Yes the top 2 flat ribbons go to the panel. You can carefully remove them and try cleaning the contacts w/alcohol or electronic contact cleaner. The 2 bottom ones are the lvds cables.

But the top 2 are the ones that are tab bonded usually. I believe there is a post about trying to repair tab bonds, but for the hobbyist I don't think its feasible.

[drussell]

Re: Vizio VF551XVT possible tab bond failure

Whats the best way to unseat them, so i can clean and re-seat them?

Those look like the type where you carefully (they are fragile) swing the brown part of the connector upwards from the ribbon cable side to release the grip on the cable.

I can't tell from that photo where they lead but be very careful with them if they lead towards the panel, you don't want to make the situation worse if they are bonded to the panel at the other end and that's where they are failing. You may still be able to shim the end at the panel with some foamies to get a better connection and some more life from the panel if that is where it is failing.

[budm]

Re: Vizio VF551XVT possible tab bond failure

Those two flat cables are for connection between the LONG PCB and the T-CON board.
The tab bondings flexible cables (has drive IC embeded on it also, https://www.badcaps.net/forum/attach...3&d=1401321146) are part the glass LED panel and are bonded to the long PCBs. To remove the cable from the T-CON, you will flip up the light brown tab up to release the cable, you must be real careful to make sure it goes back in correctly. I cannot see on the other end to see if it also has the locking tab or not, pictures are too dark to see.
The LVDS cable is the cable between the T-CON board and the main board.

[angrydingo]

Re: Vizio VF551XVT possible tab bond failure

Thanks for the help guys.

One of the connections was definitely loose. I could see the picture changing while I jiggled the one ribbon around, and then the cable just fell out! So i flipped up the tab, firmly reseated it, and voila, working TV. Haven't had the opportunity to give it a proper test run, I'll get to that this weekend

[budm]

Re: Vizio VF551XVT possible tab bond failure

Great! I hope that is all it needs.