Need help diagnosing why my TV isn't working anymore

[choucroutman]

Hello, my LG OLED55C8PLA TV stopped working, and here's what happened:
Around noon, it stopped turning on, meaning the screen stayed off, I heard a ticking sound when I tried to power it on, and the red LED light blinked 3 times. Afterward, nothing would happen for about 1 minute, and then the same cycle would repeat. A few days later, there was no more red LED blinking, and whether I tried turning it on with the remote or the power button on the back, it wouldn’t respond. I’ve tried some "quick fixes" I found online, like unplugging the TV and pressing the power button for 30 seconds to discharge any remaining electricity, but nothing worked.
I would really appreciate your help in first diagnosing what might be causing the issue, and if possible, how I might repair it myself!
If you have any ideas on what might be wrong, or how I can properly diagnose the device if multiple components could be at fault, that would be great.

Thank you in advance!
Note : I translated this text into English using ChatGPT. I am French, so sorry if there are any misunderstandings while reading it.

[Diah]

use service remote control and press P-ONLY ( Power ONLY) , the TV will boot on and you will be able to see the defect on yours screen. not repairable , if you dont owned service remote search over here in the forum i posted many other like wave, or android apk to use with any android build in IR sender for example Galaxy S5

[EazyBone]

It translated well.
Do you have a multimeter? That would be how you would start testing. They are $5-25 for something that would work in America anyway.

[choucroutman]

It translated well.
Do you have a multimeter? That would be how you would start testing. They are $5-25 for something that would work in America anyway.

Great news, I managed to open the TV, and I noticed this: the component looks completely fried, the cables are in bad shape, and there’s some liquid leaking from the component; it doesn’t look good at all. I’m attaching photos of the component in question and the entire power supply board.

Could this be the only issue? If so, what should I do?

I tried searching for the specific component but couldn’t find it, and I don’t know how to solder. Plus, could other parts have been damaged along with it? What’s your opinion?

Alternatively, should I replace the entire power supply board? They’re very expensive on "official" websites, but I found some cheaper ones on AliExpress, though I’m not sure about their reliability. I’d really appreciate your advice. Thank you!

[choucroutman]

use service remote control and press P-ONLY ( Power ONLY) , the TV will boot on and you will be able to see the defect on yours screen. not repairable , if you dont owned service remote search over here in the forum i posted many other like wave, or android apk to use with any android build in IR sender for example Galaxy S5

Are you sure It's kind of a software issue? I'm kind of sure that the problem come from the power supply, and because of it the tv wont turn on (not even the led).
Look at the pictures I just sent, maybe its more precise with them !
Thank you !

[EazyBone]

Are you sure It's kind of a software issue? I'm kind of sure that the problem come from the power supply, and because of it the tv wont turn on (not even the led).
Look at the pictures I just sent, maybe its more precise with them !
Thank you !

Red light not on doesn't necessarily mean power board. Main board also causes this, as main board sends signal for the red light.

If it was a Sony, chances are main board. If Samsung chances are PSU.

LG.. depends. This is why multimeter is important. Can't see if things work or not without it.

[choucroutman]

Red light not on doesn't necessarily mean power board. Main board also causes this, as main board sends signal for the red light.

If it was a Sony, chances are main board. If Samsung chances are PSU.

LG.. depends. This is why multimeter is important. Can't see if things work or not without it.

I don't know how to use a multimeter and I don't have a manual where its show the right V or A to have in the circuit, how can I manage to know it

[EazyBone]

Yea, you stick one lead somewhere and one lead somewhere else. Pretty easy to learn. And there is a legend on the right side of the board that tells you the voltage your looking for. But first you would check if the fuse is dead.

Of course you should only do this if your comfortable with it.. while a TV is plugged in you can obviously zap yourself. But the area on the right is the cold side of the board which is pretty safe.

This is why the forum is here. To help diagnose. We can't tell you if the PSU is dead or not because you can't test it otherwise. You can take a guess and just buy one

Yes eBay and AliExpress work fine also, I've buy most boards from eBay and rarely Ali but it's worked out both places.

[choucroutman]

Yea, you stick one lead somewhere and one lead somewhere else. Pretty easy to learn. And there is a legend on the right side of the board that tells you the voltage your looking for. But first you would check if the fuse is dead.

Of course you should only do this if your comfortable with it.. while a TV is plugged in you can obviously zap yourself. But the area on the right is the cold side of the board which is pretty safe.

This is why the forum is here. To help diagnose. We can't tell you if the PSU is dead or not because you can't test it otherwise. You can take a guess and just buy one

Yes eBay and AliExpress work fine also, I've buy most boards from eBay and rarely Ali but it's worked out both places.

Do you think it is a good idea to directly test with a different power board? Some people on another forums telled me that it can be the OLED screen who have defaults and can instantly kill the power board

[Diah]

Are you sure It's kind of a software issue? I'm kind of sure that the problem come from the power supply, and because of it the tv wont turn on (not even the led).
Look at the pictures I just sent, maybe its more precise with them !
Thank you !

this is not software problem.. its hard ware as yours Panel had OLED shorted so TV will not start... save money and don't buy any boards

[nomoresonys]

Curious Diah, how can you be sure it's OLED shorted?

[bohaboha]

Do you think it is a good idea to directly test with a different power board? Some people on another forums telled me that it can be the OLED screen who have defaults and can instantly kill the power board

hello you have to be very careful if you try to test because it is very hi voltage on the TV board . best to look at this YT video in french you will get a lot of help from this Gay Akim electronic i think
but if you fix a multimeter and follow the recommendation of the extraordinary peoples here you can make a big jump

[EazyBone]

Not sure what your even asking anymore. Good luck.

[choucroutman]

hello you have to be very careful if you try to test because it is very hi voltage on the TV board . best to look at this YT video in french you will get a lot of help from this Gay Akim electronic i think
but if you fix a multimeter and follow the recommendation of the extraordinary peoples here you can make a big jump

I suspect the power board in my device is faulty based on testing I’ve conducted. However, I’ve heard that a short circuit or other issue in the OLED screen could have caused the power board to fail. I’ve ordered a multimeter, which should arrive in about two days, to help identify the source of the problem. Is there a safe way to use the multimeter to test whether the OLED screen has issues that could cause a new power board to fail immediately? I want to avoid replacing the power board only for it to be damaged again.

[Diah]

Curious Diah, how can you be sure it's OLED shorted?

he have 2 LVDS connected between Mainboards and T-CON, if he disconnected only the lower one 51 pins the TV will start and the optic ports will lit red

[nomoresonys]

Thank you sir, so looks like in that respect it's like the led tvs.

[choucroutman]

he have 2 LVDS connected between Mainboards and T-CON, if he disconnected only the lower one 51 pins the TV will start and the optic ports will lit red

Sorry I didn't understand, if what you say is true, how can I confirm it with testing (that it is the OLED screen who cause problems)
Because I disconnected cables from power board to the middle circuit board (don't know his name), with only left the black cable between the motherboard and the power board, and I still don't get the red light or any sign of life (if its help)

[choucroutman]

I will receive a multimeter in two day for testing purpose

[Diah]

Sorry I didn't understand, if what you say is true, how can I confirm it with testing (that it is the OLED screen who cause problems)
Because I disconnected cables from power board to the middle circuit board (don't know his name), with only left the black cable between the motherboard and the power board, and I still don't get the red light or any sign of life (if its help)

Post photo on all complete boards to tell you which cable need disconnected in order to confirm the OLED Panel defect

[choucroutman]

Here a full view of the boards (at least the front side, cause to see the back of the motherboard I need to dismantles all)