lg 55ln540

[wirphotos]

My mother in law had this tv, worked great until one day. The image appears, but there are lines that form and the image is still visible.

I opened the back of the TV and noticed a noise coming from near the tcon board. If I unhook the cable going from video board to the tcon, the noise goes away. The screen has a blue screen and there are no lines. All the LED light appear to be lit from the back of the TV.

Is it possible the tcon board failed?

[budm]

Re: lg 55ln540

Please upload good clear pictures of the whole backside of the TV showing all the boards, and also the screen shot of the screen so we can see what we are dealing with.

[wirphotos]

Re: lg 55ln540

See the attached pictures. When the tcon board is hooked up the tv has a him to it.

[CapLeaker]

Re: lg 55ln540

what happens if you disconnect only one ribbon cable from the tcon to the panel, then vise versa?

[wirphotos]

Re: lg 55ln540

what happens if you disconnect only one ribbon cable from the tcon to the panel, then vise versa?

The side that is hooked up has vertical lines, the other side is a clear white screen. When I hook that one back up and disconnect the other. It's the same thing on the screen, the side hooked up has lines, the other side is white.

[CapLeaker]

Re: lg 55ln540

look at the bottom tab bonds

[wirphotos]

Re: lg 55ln540

look at the bottom tab bonds

I took the tv apart and got to the circuit board that the tab bonds are attached to. What would I be looking for?

I did replace the tcon board and that made no difference.

[budm]

Re: lg 55ln540

https://www.badcaps.net/forum/attach...6&d=1579300793
That looks like gate drive (side tab) issue, taped off method may work.

[wirphotos]

Re: lg 55ln540

https://www.badcaps.net/forum/attach...6&d=1579300793
That looks like gate drive (side tab) issue, taped off method may work.

Side tab....is that one of the tabs on the bottom circuit board?

[nomoresonys]

Re: lg 55ln540

No, side tabs are on the side of the tv, if it has them, example of "tape off" method there, need to play with tape placement sometimes to get it right: https://www.youtube.com/watch?v=j7vl7-vZEL8

[wirphotos]

Re: lg 55ln540

Think it might be a lost cause. Picture is all wiggly, you can hear a hum coming from the tv. When tcon is unhooked the hum goes away. The back lights are all on. I only see the tabs on the bottom, there aren't any on the side that I can see.

Replaced tcon board. Everything clears up when tcon or cables to tcon are unhooked. When t con is connected the problems come back.

[wirphotos]

Re: lg 55ln540

Alright tv has been sitting on my workbench. Now that we're are quarantined I figured I would make one last attempt.

I unhooked all the cables from the power board. I took readings and everything checked out. I hooked up video board and took readings, nothing changed. I took readings of back lights connection to power board. The readings we're good, whether cable was hooked up or not.

Everything checks out and the flickering sound is gone. If I hook all cables up to all boards and leave the lvds cable unhooked from the video board the flickering sound is gone. Once I hook that cable up the noise comes back. The flickering noise match's what the tv is doing.

Power board checks out
Tcon board has been changed
Backlights all light up and never flicker
Pressing on the tabs doesn't make any change

Only thing left out is the video board. Is it possible that the video board is causing the screen to do that? I also have no sound either.