Vizio e550vl has a halo or light blotch

[danman282]

I just got this Vizio working after replacing 3 back light inverter boards and now there is a halo or light blotch on the screen. (see pic.) It's only noticeable when there is a dark or black background. I'm not sure whats causing this, but I think it could be the t-conn. or possibly the lcd tabs. If someone could point me in the right direction it would be greatly appreciated. Thanks again.

[tom66]

Re: Vizio e550vl has a halo or light blotch

Looks like mura - unrepairable - or uneven backlight layers - fixable, but difficult.

[danman282]

Re: Vizio e550vl has a halo or light blotch

Is there any way to tell for sure? Do you know of any good tech articles for the repairs?

[tom66]

Re: Vizio e550vl has a halo or light blotch

I fixed backlight layers which looked similar but it's a pain in the arse and scary... you have to lift the LCD panel out and remove the layers, clean them if they are smudged or dirty (moisture/water can cause this) and then put them back in. Haven't done once since, the TV I did it on was a freebie 42" so I had little to lose.

[danman282]

Re: Vizio e550vl has a halo or light blotch

Thanks for the info. That does sound like a pain. I'm in to this tv for $375 so I may just risk it, I'm not sure yet. I'll have to do some more research.

[tom66]

Re: Vizio e550vl has a halo or light blotch

$375? That is a lot of money to spend. personally I would just bail out now and sell it with the fault and get your money back.... and someone gets an "ok" 55 inch for cheap. So, so easy to break that panel while doing that, or damage a tab, or smudge it...

[danman282]

Re: Vizio e550vl has a halo or light blotch

Thanks for the info and your opinion. I think I'll keep it and get my money out of it and maybe fix it when I can.

[Alastair E]

Re: Vizio e550vl has a halo or light blotch

Hmm--So, this 'mura' is a backlight diffuser issue?

Or is the actual TFT plate and the polarising films bonded to each side of the actual glass LCD part the problem?

If its the diffuser--then apart from the danger of damage through dissassembly/re-assembly when replacing the diffusers, there shouldn't be a problem....

Ive stripped down a few assemblies for various reasons, reassembled etc, and while a chore--isnt really a problem.....
I did one on Friday. a 26" Panasonic with a Cei-Mei display, the original had a faulty tab and the replacement a faulty backlight tube....

I used the original backlight 'box' with the replacement's TFT....

[tom66]

Re: Vizio e550vl has a halo or light blotch

It's reasonably easy with a 26" display, but remember, this is a 55" sheet of glass...

Mura of the panel appears to be related to the layers in the panel separating slightly, but I've never found detail on the exact cause.

Sometimes mura is caused by the diffuser films only.

I fixed a 26" Panasonic like yours with a tab shim and it was fine, did you find that not to work?

[danman282]

Re: Vizio e550vl has a halo or light blotch

I haven't gone that far into it and by the sound of it I have to do a lot more research before I do. Thanks for getting me pointed in the right direction.

[freakaftr8]

Re: Vizio e550vl has a halo or light blotch

Agreed. Fixed one of these not too long ago. Rear diffuser was actually melting! Have some parts if you need. Noticed your close. But looks like yours is just dislodged or you may have assembled the pieces in the wrong direction.

[Alastair E]

Re: Vizio e550vl has a halo or light blotch

It's reasonably easy with a 26" display, but remember, this is a 55" sheet of glass...

Mura of the panel appears to be related to the layers in the panel separating slightly, but I've never found detail on the exact cause.

Sometimes mura is caused by the diffuser films only.

I fixed a 26" Panasonic like yours with a tab shim and it was fine, did you find that not to work?

Ah--OK right, a few causes possible then!

The 26" Pan-=- I had tried a few times to cure the tab-bond, it would last a few hours to a few days, but eventually--I got pissed at it and decided to change the lot!
--Even that didnt go well as the backlight tubes were causing 2 sec to black on replacement screen!