LG no picture

[nosugartonight]

Hay everyone. Have this LG 55ls4500-ud. Has sound and backlights but no video. Do I have a bad panel or t-con. All voltages on power and main are good. I checked volts on one side coming out of tcon where I see test points and have 6 volts on all. Didn't check other side because I don't see any test points. The hole screen glows when powered on. Added 3 photos one with everything hooked up . Others with each side of tcon unplugged.

[Andrew F. Ali]

Re: LG no picture

Could we get a focused hi-res picture of the T-CON Bd, please?

[freakaftr8]

Re: LG no picture

That looks like a shorted MLCC capacitor on the panel source driver boards. Themes are located across the bottom of the LCD panel.

[nosugartonight]

Re: LG no picture

This is the best my phone will do . To the second reply your talking about the buffer boards along the bottom edge.

[nosugartonight]

Re: LG no picture

Can that board be changed or do they have bonded tabs

[freakaftr8]

Re: LG no picture

Yes I am referring to the bonded boards at the bottom of the panel. They are bonded tabs but if you take close up pictures of each side I will show you which capacitors to test. Maybe fixable if you can remove it safely without damaging the board

[nosugartonight]

Re: LG no picture

I'll post photos ASP.

[nosugartonight]

Re: LG no picture

Sy took a few days to post the pictures. I assume you just wanted pics of the front. Pics are from center at tcon to the end. I don't see anything blown visually. Before I go probing. What should I check and how. Thanks

[nosugartonight]

Re: LG no picture

Can someone add further help.

[budm]

Re: LG no picture

Check the resistance between the two legs of ALL those MLCC (Multi Layer Ceramic Capacitor), I.E. C204, C225, etc.

[nosugartonight]

Re: LG no picture

Thanks budm. I'll post back

[nosugartonight]

Re: LG no picture

Hay budm , these measurement's are on the side where,when the tcon ribbon is unplugged the screen is black with lines. Starting from middle.
C204 .388
C221. .387
C224 .648
C231. .387
C234. .647
C241. .000.3
C244. .0001
I did not check the other side,when the tcon is unplugged that side is white.

[freakaftr8]

Re: LG no picture

Sorry wasn't on this weekend I was busy rebuilding my deck. Check those readings with the corresponding MLCC caps on the other side and post results. I'm suspecting a shorted C241 and or C244 to be your problem.

[budm]

Re: LG no picture

Hay budm , these measurement's are on the side where,when the tcon ribbon is unplugged the screen is black with lines. Starting from middle.
C204 .388
C221. .387
C224 .648
C231. .387
C234. .647
C241. .000.3
C244. .0001
I did not check the other side,when the tcon is unplugged that side is white.

What Ohms scale is the meter set to? Ohms, K Ohms, M Ohms?

[nosugartonight]

Re: LG no picture

M ohms. When I first tried to measure the mlcc's. I was touching the ends and for some reason I wasn't getting a reading. So I touched on the top ends. That's how I got all the readings. Just to be sure. I rechecked by touching the ends and got different readings on all. Here are the readings and I made sure I was getting good contract.
C204-.426
C221-.425
C224-.651
C231-.431
C234-.653
C241-.433
C244-.654
Other side,
C104-.422
C143-.422
C144-.653
C134-.653
C133-.424
C122-.425
C120-.655
I guess this changes things.

[budm]

Re: LG no picture

If the meter is in M Ohms setting then those readings are showing the Range of 422,000 ~ 655,000 Ohms.
If you have bad cap, the resistance will usually be <10 Ohms.

[freakaftr8]

Re: LG no picture

There's only 6 ribbons total? 3 in each side? Can you post a picture of both bottom boards together? Basically the whole bottom of the panel?

[nosugartonight]

Re: LG no picture

I can't get both boards in one shot. Two with flash,two without. Is there any fuse's on the boards that I can check.

[freakaftr8]

Re: LG no picture

Now there are no fuses to check on those boards. If those bigger capacitors check OK how about the smaller ones across the bottom of the boards? If there are no shorts then I would only assume that either it could be a COF ribbon failure on the panel. You could always try replacing the tcon but I doubt that's going to alleviate this problem

[nosugartonight]

Re: LG no picture

I'll check the other mlcc's . About the tcon I assume you seen that I posted the voltages on the outside. Is that right? 6 volts. Also I didn't check other side because there no test points. The side I did check was side going black. And wouldn't the screen side that goes black when tcon ribbon is disconnected, where the problem is..