Chosen Solution
Hi guys, A few days ago my TV screen suddenly went black and I don’t quite know what to do. Basically, if I turn it on the LG logo will appear for about a second or so and then the screen goes black. although backlight stays on. The only button on the remote that does anything is the on/off one. Called up 2 tv repair shops and both told me almost straight away that it sounds like the panel is dead and I need to basically replace the whole screen (a $3,000 repair), which I don’t quite believe. When I took the TV off the wall and tried turning it on again a few days later - it worked fine for maybe 10 seconds and then the screen went black again. Maybe there is a loose connection somewhere or something. Any ideas? I hope there’s something I could try before I throw it away. The model is LG 70" UH635T, I could find it in the list so had to choose a random LG model when posting this question Thanks!
@crashxxx backlight on without video is usually a main board problem you did not tell us if you get any sound. You need to check out all your video inputs and see if that changes anything. If it does not remove the back of the beast and take a look at all the boards for any obvious damage (leaking or domed looking caps etc.). Post pictures of your boards so we can see what you see. Use this guide Adding images to an existing question for that. The problem could be the panel but it could also be the power board or the main board.
Had same problem with a LG 5510 Was watching TV and screen just faded to black sound remains Logo comes on upper left for few second’s then fades to black Disconnected everything gave the back a good vacuum noted was dusty near some of the ventilation slots Screen came back on after restart only been 10 mins but colour contrast vibrant looks good
Hold down power button on bottom of tv for 10 seconds when it’s on.
It’s a problem with the motherboard. solution may sound extreme but it works. Remove board and place in Warm oven for 20 minutes. Allow to cool , reinstall and all should be good.
the Led back light is bad, leds connected by series, one dead all will not work, check this video: https://youtu.be/LaV6aQ8LIpw Update (11/17/2021) If the logo showed for couple seconds then off then it could be the leds back light is bad, maybe just one of 40-10 less.
I’ve been stressing about this. My tv would go dark only if the picture was dark or tv seen was at night so I would crop the picture and have a steady on background on the section that would go dark. The other strange thing is that in initial setup mode the TV would stay on with perfect picture forever, but when done it would go dark again blank u can see picture only by shining a torch onto the screen and also barley. But for the past week my picture has returned I no longer have to crop the screen everything is as it should be. The issue was power, we unplugged alot electronics changed the multiplug and immediately saw a difference, check power supply to the socket as well
Have you tried a firmware update . It worked on mine for black screen no signal
Our backlight is failing. Seems to be an issue with these LG TVs. Turns on, then screen goes black. Sound working and you can see screen using bright flashlight. We got our LG 60 inch working again by turning the backlight setting down using these options: Gear Icon > … > Picture > Picture Adjust > Backlight. Our Backlight was set at 100. I would suggest putting your backlight at 10 or less NOW. We have it set to 6 and TV works again. I watched video on replacing the LED backlights and it is very difficult for not for a nonprofessional to perform. We had a bright non-LED flashlight to be able to see the screen to lower Backlight setting. Not easy with LGs stupid Magic remote. I will never buy another LG TV.
