LG 50UH5500 need fix

[nomoresonys]

Re: LG 50UH5500 need fix

Maybe you just need to add a little solder, one video here, he did a one led replacement, it's an lg but not your model or size, it gives you the gist of it tho: https://www.youtube.com/watch?v=YrZ4bAFiUg8

[nomoresonys]

Re: LG 50UH5500 need fix

Important that you glue the lens back on in just the orientation that it came off to avoid any possible halo effect when replaced, shouldn't be too hard tho you have the others as a guide.

[slip]

Re: LG 50UH5500 need fix

So, I think the problem with that one led was that it was separating internally somehow. That's the only explanation I can think of because it continued to fail testing, even after being removed from the strip.

I decided to try putting the tv together with a bit of copper wire where the bad led should be. I forgot to put the caps back on the working leds though which is noticeable when looking at the screen.

So, now the power doesn't cut out on it's own. No blinking red light. Leds light up and stay on but there's no picture; not even the lg symbol at this point. I didn't seem to forget any plugs. Any idea?

[nomoresonys]

Re: LG 50UH5500 need fix

Check that you have voltage on each side of the tcon fuse, negative lead on chassis ground positive on each side of fuse.

[slip]

Re: LG 50UH5500 need fix

how do I do that?

[nomoresonys]

Re: LG 50UH5500 need fix

Probably need to take the shield off the tcon, there should be a fuse that looks like one of the little ceramic capacitors labeled starting with Fxxx, set your meter to 20 vdc, put negative probe on metal chassis of tv and positive on each end of fuse probably looking for around 12 volts on each side.

[slip]

Re: LG 50UH5500 need fix

I think this is my tcon board but I don't know the part you're referring to.

[nomoresonys]

Re: LG 50UH5500 need fix

White, has a T on it, labeled FP1, right by the connector there.

[slip]

Re: LG 50UH5500 need fix

I only get 13v on one side

[nomoresonys]

Re: LG 50UH5500 need fix

Ok, now put meter in diode mode put a probe on each side of fuse, will beep or read near 000 if good, appears to be a blown fuse, this is diode mode so test with tv OFF and UNPLUGGED from power.

[nomoresonys]

Re: LG 50UH5500 need fix

For testing you can use a pico fuse soldered on top of the fuse with roughly the same amperage.

[slip]

Re: LG 50UH5500 need fix

Sorry for misreading but I got a reading of 1 on one side and it was blank on the other side so I rechecked the voltage and it did read 13v on both sides. I must've had it in a bad spot during the first reading. Sorry, I know your trying to help. I'm not trying to over complicate this. Thank you for taking the time to help me!

[budm]

Re: LG 50UH5500 need fix

Since in post 1 you did indicate that you can see image on the screen before, and now after disassemble the panel and the put it back together and now you do not get image any more, I would re-check all the cables and re-seat them again.

[slip]

Re: LG 50UH5500 need fix

I did multiple times but still nothing.

[nomoresonys]

Re: LG 50UH5500 need fix

Try a retest as in post #11, see what you get.

[slip]

Re: LG 50UH5500 need fix

93.7
93.7
93.7
19.7
22.5
19.7

It seems likely that the 22.5 is from the strip that I bypassed the one bad led. Power to mainboard is at 13v now and lights stay on but no picture.

[nomoresonys]

Re: LG 50UH5500 need fix

Strange indeed, t-con supplies picture right? might have a bad t-con or connection, try cleaning the ribbon cables from t-con to panel, some use a pencil eraser, make sure your lvds cable to t-con is clean and secure.

[slip]

Re: LG 50UH5500 need fix

The eraser did make the cable-end look cleaner but same issue.

Another thing I just realized I forgot to post before was that an image came up at one point a couple days ago that said "input locked" and it was bouncing around the screen with some distortion right above it so, I figured it was a bad connection somewhere and reconnected everything but it never came back. Not sure if that helps at all.

Also, I noticed 2 buttons on the main board next to the metal plate. Any ideas what they might be?