LG 43UK6090 no image

[alfatv]

Suspect bad panel, but looking for advices especially from those familiar with this model.
TV is turning on, there is backlight and sound.
The picture is grey.
Main supply voltage to the panel (big electrolytic cap) is quickly is turning off after power up, but it stays on on if panel is disconnected.
I checked for shorts, nothing obvious.
There are few types of panels and main boards used in this model, mine is with 2 panel connectors inwards like here:

https://www.ebay.com/itm/LG-EBU64868...M/363237919773

[Diah]

Re: LG 43UK6090 no image

99.9% panel cracked

[alfatv]

Re: LG 43UK6090 no image

No, it's not cracked, but I will double check inside.

[budm]

Re: LG 43UK6090 no image

Please attach the pictures of the whole backside of the TV showing all the boards and the screen shot of the panel when TV is turned on so we can see what we are dealing with.

[alfatv]

Re: LG 43UK6090 no image

I removed the panel, no cracks at all.
See attached pictures, one of them shows lines when TV is turning on. After that it goes steady grey.
Image is always grey no matter what cable to panel is connected.
But power supply shuts down only if the right side (looking from the front) is connected.

[dick_barton]

Re: LG 43UK6090 no image

Can you post photos of the long thin circuit board connected to the lcd panel.

[alfatv]

Re: LG 43UK6090 no image

Here is long board, 6 COFs total

[alfatv]

Re: LG 43UK6090 no image

Just got image out of it with tape method.
Had to cover about 20 pins or so on the left side of connector.
Tried to cover less pins, but it either stops working or starts flickering or there are line patterns on the right side.
Experts, what's going on and what to do next?

[brucetv]

Re: LG 43UK6090 no image

You have a short in one or more MLCC's on the lower driver boards for the panel. The UK series is plagued with this problem and you have to remove the shorted cap to get the panel to fire up. It's a slow pain in the ass process. Life is NOT good with LG crap panels.

[alfatv]

Re: LG 43UK6090 no image

Brucetv, thanks for advice, I already tried to to find shorted caps, bus was not able to.
Are they dead short or somewhat leaking? Should I use resistance or diode check?
Or do you mean removing them one by one?

[dick_barton]

Re: LG 43UK6090 no image

Set your meter to ohms and check for very low resistance close to very low to zero ohms