LG 55LM6200 part of image is darker

[alfatv]

Please take a look at picture, seems to be panel related.
Sometimes can see footprints from other scenes in that darker area.
Already tried to clean and swap cables between T-con and panel, no effect.
What voltage can be responsible for that? Any hints?

[Diah]

Re: LG 55LM6200 part of image is darker

call service menu E-Z Adjust and from there ADC or test pattern to see if any change.

service manual

[alfatv]

Re: LG 55LM6200 part of image is darker

Same thing with test pattern

[budm]

Re: LG 55LM6200 part of image is darker

Is the tab bonding board on the bottom edge of the screen? I would inspect that section of the tab bonding board.

[Diah]

Re: LG 55LM6200 part of image is darker

.....

[alfatv]

Re: LG 55LM6200 part of image is darker

Oops, here we go, I should have done it before asking.

[budm]

Re: LG 55LM6200 part of image is darker

Well you found the problem, it is probably due to people spray glass cleaner on the screen and it drips down to the tab bonding board.

[alfatv]

Re: LG 55LM6200 part of image is darker

This is beyond my capabilities.
If anyone is brave enough, I am giving this screen away for free, pickup only.

[ReeceyBurger123]

Re: LG 55LM6200 part of image is darker

This is beyond my capabilities.
If anyone is brave enough, I am giving this screen away for free, pickup only.

Yeah would have trace them via ports back to somewhere too, would be a hard repair not worth risking the COFIC being damaged either

[RDC55]

Re: LG 55LM6200 part of image is darker

That's the big side as far as pitch is concerned:-) Seems you could possibly repair an open if that is the issue and since they are redundant you can just look at the others to see how it should hook up if there is any doubt. Using one strand of finely stranded wire (about .12mm) should be easy enough to work with.

[angelos]

Re: LG 55LM6200 part of image is darker

You need a microscope! I once cut the wrong CKV lines on a tv and had to resolder those minute tracks with thin wires. What a nightmare. Good luck on the eye strain.

[alfatv]

Re: LG 55LM6200 part of image is darker

Please somebody who has this screen, share a picture of this section (post #6, 8)

[budwich]

Re: LG 55LM6200 part of image is darker

you might post closeup pictures of all the edge board connectors. As suggested, you may notice how the section is designed in the other connectors. You might get lucky or someone might see a "pattern". Then, perhaps consider doing some form of small wires and conductive glue... just a suggestion.

[mlemon]

Re: LG 55LM6200 part of image is darker

This is beyond my capabilities.
If anyone is brave enough, I am giving this screen away for free, pickup only.

I had somewhat similar situation where looks someone had sprayed some sort of chemical on the display and leaked down to the cables, however not as bad as yours.
After I cleaned mine, luckily the cable was ok but found a small a blown trace and a couple of burnt capacitors. I managed to fix the trace by jumping with a fine wire and replaced two burnt caps. TV came back to life with beautiful picture.

I have never done this type of microscopic level de-soldering/soldering, was not pretty finish but got it to work. Just use fine solder tip and fine solder 0.3mm or less and I think you have nothing to lose and feels great afterwards after fixing it. And looking closely at yours, looks some of the traces in the cable two in one so it helps a bit. Good luck.

[ReeceyBurger123]

Re: LG 55LM6200 part of image is darker

You need a microscope! I once cut the wrong CKV lines on a tv and had to resolder those minute tracks with thin wires. What a nightmare. Good luck on the eye strain.

Would be possible though, I've done it before on a liquid damaged panel. Bit of a mess about if I don't say so and make sure you have steady hands

[alfatv]

Re: LG 55LM6200 part of image is darker

Thanks for support, I am not giving up yet, here is what I figured out.
Some of connections are supply voltages and apparently are duplicated, so it may be OK not to connect them.
What is really missing is 6 gamma voltages and I will focus on that.
I was able to remove part of the tape, thanks to corrosion under it, so at least I have access to connections.
The wire is from solder wick, the thinnest I could find.
I use Iphone as microscope.
Let's see how far I can get.

[alfatv]

Re: LG 55LM6200 part of image is darker

With help of my gf holding iphone, I managed to solder those 6 wires.
Also had to add one jumper wire to the next tab as one of vias was corroded.
It worked right away the way it should be.
The case is closed, thanks everyone for help and inspiration.

[dick_barton]

Re: LG 55LM6200 part of image is darker

Well done. Excellent job. An example of never give up.

[faxygian]

Re: LG 55LM6200 part of image is darker

Great job ... very good

[mlemon]

Re: LG 55LM6200 part of image is darker

Awsome, happy ending !