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LG TV - powers on, but black screen after LG logo, backlight is on

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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!

Risposto! Visualizza la risposta Anch'io ho questo problema

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My LG 55 TV turn on, show the LG symbol for 2-3 seconds then goes to black screen/shut downs. Anyone know if this is the power supply or main board. I have sound through the surround sound but not TV.

da

Stan what was the solution? did you manage to fix your TV? I am having the same problem

da

Mine just went too!….The same %#*@ problem!!!

da

Mine went out too. Haven't found a solutions

da

Hi guys,

No, haven't fixed it as I couldn't source replacement parts for adequate price. The TV is just sitting in my garage at the moment.

da

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@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 Aggiungere immagini ad una domanda for that. The problem could be the panel but it could also be the power board or the main board.

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19 Commenti:

Hi There,

Took the back cover off and uploaded the images of all 3 boards.

Turned the TV on after a month or so and it worked again for about 10 min. and then the same issue. I noticed a few more things:

- There is a green LED LD701 on the power board that starts blinking when the screen goes black (blinks 5 times)

- The red standby light blinks 3 times when I I turn the TV on and before backlight turns on

I was thinking of trying replacing all 3 boards (starting with the power board) to see if it fixes anything. Sounds like a better option than buying a new tv... not sure if I should really start with the power board though.

Thanks for your help!

da

@crashxxx does the sound remain when the image turns black? this sounds more like a main board issue than a power board issue.

da

I was playing a movie via USB stick. As soon as the screen goes black - there is no sound. Basically the only thing that is on is the backlight. It is also weird that if I don't touch the TV for a week - it will turn on again and work fine for another 10min or so. I also realised that there was a thunderstorm when the TV died and on the same day my power board died (unfortunately, the tv was connected directly into the wall socket so there was no surge protection). Not sure if this info is useful. It feels like there is some sort of protection mechanism that kicks in and shuts the TV down.

da

@crashxxx all of this "no sound. Basically the only thing that is on is the backlight." and" It is also weird that if I don't touch the TV for a week - it will turn on again and work fine for another 10min or so" sounds like a bad component on the main board. It comes on for awhile until possibly the failed component heats up enough to quit working. That'll be the green board in your pictures. Remove the EMI shield and lets see what is going on under there.

da

Hi.. Did you fix your tv finally?

da

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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

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So perhaps in my case was dust over power supply area??

da

Mine did not have sound. Mine just died last eve, and each time I tried to restart it, I saw the LG logo, and my HDMI input info, and then it faded to black w/in 2-3 seconds. Unplugged, vacuumed, and dusted the ports, and then restarted. It did the trick! The set rebooted and ... Voila! Good to go!

da

Now it s saying no signal

da

My lg TV screen is fading to black after a few minutes on. The sound remains,but no visual from screen. Any help would be greatly appreciated

da

Had black screen with flashing red light. I unplugged everything, took the back cover off and carefully vacuumed all of the inputs and circuitry and it's now going well again - I had been trying to fix the thing for hours and was nearly ready to give up when I tried this. Thanks @Windy Freckle

da

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Hold down power button on bottom of tv for 10 seconds when it’s on.

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You are the bomb! This worked. Saved me a ton of $$$ and stress.

da

Wow!!! Dude...I literally just did the same think (except with the remote) and it worked!!! What in the heck???? why? what was it can you elaborate??? but thank you soooooo much!!!

da

Awesome. I did exactly the same thing and poof, problem fixed....

da

Yes it works. But it hasn’t cured the problem. I have to do this 6 or 7 times to get my tv to turn on every time. Each time I get a bit further forward.

1. No reaction. Unplug and re plug in.

2. No reaction. Unplug and re plug in.

3. Logo appears and goes off.

4. Logo appears and a line appears at the bottom of the screen.

5. Logo then a still picture that fades.

6. Logo then a pic that moves for 1 second freezes and fades.

7. Works.

And I have to unplug it after the first couple of times or it doesn’t work.

da

Mine just fades in and out

da

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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.

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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.

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7 Commenti:

not helpful. I managed to squeeze my 16 inch telly into the oven and set the heat to 180 degrees, but this resulted in the plastic melting around the edges. perhaps 180degrees is too hot? tv still doesn't work. sad face

da

I’m sorry to say that you must have misunderstood the instructions on how to do this procedure. You ARE NOT TO PLACE THE ENTIRE TELLY INTO THE OVEN FOR GODS SAKE MAN! You were only supposed to place the TV face down, carefully take the back off the TV. Unclip and remove clips off of the motherboard which is a square computer board that has soldering on it that needs re melted. You probably need a new Telly now.

da

What's a good temp and how long? Is it the green board or orange? Is this something you've done before? I see nothing about this on the internet which has me questioning the whole thing. At this point im out of options.

da

A good way to tell if you have one of these LG's is to look up the main board for that tv.. if it's hard to find that main board if it's sold out everywhere and even better if you find it but if they want ungodly amounts.. and if the LG was made in that time period I was talking about there's a good chance cuz they are rare and hard to find Main boards! If you want to know if you have one of these models, I'm one of two people in the entire world that offer a repair service where we do the repair right! You can find me at multiple personalities premium TV repair and services on Google or on facebook.. also Fire TV bullied on Facebook and I'm on my 4th semi getting large YouTube channel as Fire TV bully.. even the guys who were offering repair services and just throwing it in the oven we're charging more than I was. Lol! I started my business to help people so that's what I do! I can repair your existing board and I have dozens of those rare main boards available for sale

da

How does someone get in touch with you?

da

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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.

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You are a life saver I thought i had to throw mine in dustbin. What happened was my LED worked fine for half an hour and then screen goes black if i turn it off by remote and turn it on again It would turn on but this time it would only remain on for 5 mins max. By applying your method now the problem has solved so probably it was led light that was the issue.

da

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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

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Have you tried a firmware update . It worked on mine for black screen no signal

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How do you update with a black screen?

da

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This just happened to me. I always turn the tv on and off only with the remote and the tv remains on stand by. The logo came on when turned on by remote then the screen went to black and the sound was still working. While the set was still running I turned it off at the wall plug switch waited about 5 seconds then switched it back on and poof...picture working.

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Have this problem. Just out of the blue, faded to black and never came back.

Every time I power cycle it the logo comes on then the fade to black.

It is NOT a problem with the backlight since you can see the backlight moving when you move the magic remote.

It is NOT the mainboard: I tried changing to a new main board. No go.

It is NOT the power supply: I tried changing the power supply. No go.

The only thing left is the panel itself, but the drivers chips are literally attached to the ribbon cables of the panel.

So it's basically a 65" flat brick now. Bought a Sony Bravia, SOO much better.

I just really hate throwing this one into a landfill. >:{

I might try a heat gun gently to the driver chips on the ribbon, but I doubt that will work. I've seen several other posts about this same issue, but no one has really tried to go to the depth I did. The repair shop even said I've basically tried everything that can be done.

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2 Commenti:

I have LG 55LA 6205 and problem is similar. initially stays on for about ten minutes and than video goes out and sound stay on. I checked the voltages going to the back panel and they are 135 and 183 at the the + point when the video is good than voltages drops down to 90 volts and video goes off. Any suggestions?

da

I have a LG TV with model number 47 LA 6200 the screen is black too, but it has sound. When I turn it on the back light flashes and go off to a black screen. When I turn it off the back light flashes as well. When the TV is on and I shine a flashlight on the screen, I can see pictures moving. I tried the trick above by holding down the power button for 10 seconds when the TV is on but that did not fix the problem.

I took off the back of the TV to see components and when I unplugged the cable from TCON to the logic board, I hear sound and the screen is still black. When I shine the flashlight on the screen again there is no picture moving. I reconnect the cable and shine the flashlight again and see pictures moving.

Any idea?

da

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I have a similar problem. TV screen turns black after a few seconds, sound still ok.

Today I tried to "bake" :) the mainboard in the oven as described in this video https://m.youtube.com/watch?v=c7p4qsTYXU..., but the carton I placed it on caught fire, the smoke smell still persists in the apartment after a few hours of leaving all windows open.

I will try to find a replacement mainboard, see if I can fix the issue like that. Diagnosing which component is faulty is an interesting challenge, just a bit above my current skill set :)

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I had a same issue, where the screen was turning back in a sec from the time the LG logo appears. As mentioned above, I was holding the power button for 10 sec and did it that way for 5 and more times and then it worked! It’s a surprise, but I’m going to watch if the issue will return.

Thanks admin for your support!

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Stan sarà eternamente grato.
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