LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

[alfatv]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

That's an interesting approach. How many pins should I try? Half of the cable?

I did it only once on UK series, was about 12 pins and result was pretty good.

[Noobwithamultimeter]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

Try to cover more pins, so you isolate the the whole group of pins driving bad side.

That's an interesting approach. How many pins should I try? Half of the cable?

[jjanssen7]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

In my experience it's just the luck of the draw... the degree the tape method works depends on where the screen is shorted. with some, faint lines is the best that can be done.

[alfatv]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

Try to cover more pins, so you isolate the the whole group of pins driving bad side.

[Noobwithamultimeter]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

After a lot of fussing with the tape and trying different pins and combinations I've landed on the most successful result. The least amount of pins I can cover are pins 11, 12 & 13. The picture is solid, color is correct and no flicker occurs. There is however very fine lines in the entire image, top to bottom.

Just want to share this information in case this becomes a predictable fault in this particular panel. I have watched a few videos on youtube and the best fix for a shorted panel seems to be the tape method. They discovered there parallel lines in the ribbon cables and if you cover them, the picture clears right up. https://www.youtube.com/watch?v=kUWapOBtm0Y

Only question remains: how is it some owners report a perfect picture with this method yet I am still seeing lines in mine? Is there some perfect amount of pins to cover and how can I determine the correct ones? Could a combination work? Like say first 1 & 2 pins covered, skip a few then cover 4 etc... boom perfect picture. I have yet to arrive at that result but I am determined since this set has the potential to be the best quality image out of all the tvs I have found.

[Noobwithamultimeter]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

Also REALLY hoping I don't have to repair these tiny caps:

[Noobwithamultimeter]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

Saw something interesting. There are little gold contacts along the board inside that controls the video signal. Some of them have conductive tape, some do not. One had the tape peeling from it when I openened it to look. Could this be a grounding issue? I'm really crossing my fingers on this one. I wonder if I put some tape on that and make the contact better it will be fine.... Picture:

[Noobwithamultimeter]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

So I removed one long metal guard along the bottom of the screen and when I looked at the sides there appear to be no gate drivers on the left and right sides of the TV. So I am going to focus on the left side of the panel first since I think that is the side that is affected.

[Noobwithamultimeter]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

Ok back at the frame removal, here is a photo of the whole back and I've indicated what line I've been tape masking with different results.

[ReeceyBurger123]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

Put the Tv on the table on a cloth screen upwards, go around it take the screws out, remove the frame bit by bit or if it’s a solid frame start lifting at the end opposite to the drivers and pcb. Needle DMM probes are advised as you don’t want to put a load of pressure of the small parts with larger probes. I’ve fixed a SONY 55” 4K set that had 1 shorted ceramic cap in a bank of like 20 in parallel it takes time, having an LCR meter can help track down the lowest point of resistance too.

[Noobwithamultimeter]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

The mlcc's are integrated into the panel. Only problem is I'm nervous about getting the outer frame off as I can't find any youtube guides on this model yet, also once I get there I have no replacement capacitors.

[ReeceyBurger123]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

You’ve almost narrowed it down to the panel, start doing some resistance checks.

[budm]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

My best guess is pins 11-14 are affected because I can see a solid image with them blocked, although there are quite a few lines in the image. Also the color is correct. Blocking other lines causes the left side of the image to go kind of slightly lime green due to the yellow being off instead of yellow.

Here is where I think the lines lead to on the mainboard. There is no t-con board in this set.

LCD TV will have T-CON. It can be stand alone T-CON board, integrated T-CON into the LCD panel, or integrated T-CON into the main board.
Can we see the pictures of the whole back side of the TV showing all the board.

[Noobwithamultimeter]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

So it's possible the failure is mainboard related? Could be a mlcc on the mainboard or on one of the gate driver tabs? I think the tabs are very tricky to solder on.

[ReeceyBurger123]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

The lines pull though a via to the other side of the pcb a magnifying glass would be a big help, they also feed too another part of the board on the top. I’ve seen even the smallest of MLCCZ caps fail short, easy to test multimeter on ground and measure each side.

[Noobwithamultimeter]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

My best guess is pins 11-14 are affected because I can see a solid image with them blocked, although there are quite a few lines in the image. Also the color is correct. Blocking other lines causes the left side of the image to go kind of slightly lime green due to the yellow being off instead of yellow.

Here is where I think the lines lead to on the mainboard. There is no t-con board in this set.

[ReeceyBurger123]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

Crazy. I have it narrowed down to 4 leads covered now. Working on a smaller and smaller piece of tape. Color is correct but there are lines still. Getting very tricky with these tiny pieces of tape.

Can you trace where they feed too ?

[Noobwithamultimeter]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

Crazy. I have it narrowed down to 4 leads covered now. Working on a smaller and smaller piece of tape. Color is correct but there are lines still. Getting very tricky with these tiny pieces of tape.

[budm]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

Bad caps can be replaced if you have experience with SMD repair and have proper tools.
Example of bad MLCC:
https://www.badcaps.net/forum/showth...44#post1043044

[Noobwithamultimeter]

Re: LG 55UJ6200 BEFORE & AFTER tape fix/fine tuning success

You can try testing resistance of the MLCC (Multi Layer Ceramic Capacitors) on the tab bonding boards to see if any of them show low resistance reading.

I'd have to take a apart the frame to get at them. Are they repairable/replaceable?