LG OLED55C9PUA power problem

[EazyBone]

Hello, trying to fix C9 55 inch. I have pulled the back and all looks completely normal with nothing burnt so far. This is first time attempting to fix a tv so any help is appreciated.

Problem. I hit power button, red light on TV turns off and tries to turn on, no picture shows up and then shuts off. This occurred after house power turned on and off, not from a storm.

I have tested the power going from power supply to main board, all 12v and 20 volt readings are proper when I hit power button.

The power supply to t con is different story.
This reads

22v
22v
22v. / 12v
" /12v
"
"
"
Gnd
Gnd
Gnd

I hit power and 12v reaches 12v for couple seconds and drops as tv turns off
The 22v reaches maybe 16v and drops immediately back down. It never reached 22 v like the other side.

My question is, is there a way to test the power supply pins such as taking the clip out and seeing if it reached 22v without the tcon connected?

Is it already known by this test that the TCON is the culprit?

Am I in over my head? Lol would appreciate some help. I only have a multimeter
And am getting some tweezers for it later today.

First picture is power supply clip where I am supposed to get 22v to tcon
Second picture is just bigger so you can see the rest of board

I don't want to just buy a replacement tcon or power supply guessing. Thanks yall

https://ibb.co/nbf7Bmh

https://ibb.co/XxgD3R4

[markolino]

Re: LG OLED55C9PUA power problem

maybe you solved the problem?? when you turn on the TV with the remote control, how many times does the red light blink?

I have a similar problem. the menu light flashes 3x

[EazyBone]

Re: LG OLED55C9PUA power problem

maybe you solved the problem?? when you turn on the TV with the remote control, how many times does the red light blink?

I have a similar problem. the menu light flashes 3x

I think the issue lies with the T CON piece. I ordered a new one already. I took the connector out to the tcon and the power supply sends 22v and 12v on all the pins and stays constant when not connected to the tcon. When connected I get the issue. So the tv turns "on" (no screen) when that is disconnected and stays on. So maybe it will be fixed with replacement. We can hope

[markolino]

Re: LG OLED55C9PUA power problem

And you have 3x red blink light?

[EazyBone]

Re: LG OLED55C9PUA power problem

And you have 3x red blink light?

No sir

[markolino]

Re: LG OLED55C9PUA power problem

I have a different problem, you can look at my post. the video is also up

[Diah]

Re: LG OLED55C9PUA power problem

disconnect the socket 20-24V between PSU & T-CON driver boards...... all other cable and LVDS should be connected as original then turn on.... give notice to optic output socket on MB if it lit red mean the set are on and responses to RC

[EazyBone]

Re: LG OLED55C9PUA power problem

So I disconnected the 20v to tcon and the same symptoms occur. The tv light in front goes from red to black for 2 seconds then I hear a relay sound and it turns off and red light in front becomes solid again.

I don't see any light as you say on the optical of MB at any point during any testing. I also don't see that there is even a light there.

I am still doing some testing myself.. I have found that with all cables connected except for one shown in picture and circled then the tv turns "on" and I don't hear switch and the tv blinks 3 times and stays on. There is no picture obviously but it stays on. All the 22v and 12v from PSU to tcon also stay constant. All voltages and everything on all boards are correct with that ribbon disconnected. They all stay constant as well.

Any other direction as to what this could be?

https://ibb.co/jH3M0VQ

I have also disconnected the tcon to panel ribbons and left all other connections on and it does the original symptoms. Again once I disconnect the ribbon in the picture the tv stays on.

Would this possibly mean tcon failure as once I connect to tcon this is when the tv auto shuts off, even with panel disconnected. Ribbon from main board to tcon bad? Or MB bad?

Lol any other test or lead would be helpful from anyone.

[EazyBone]

Re: LG OLED55C9PUA power problem

Anyone more help? Or a link in this issue?

[EazyBone]

Re: LG OLED55C9PUA power problem

Well I fixed it. Not sure why no one responds to new people really.

[markolino]

Re: LG OLED55C9PUA power problem

How to repear ??
Explane. Thanks

[EazyBone]

Re: LG OLED55C9PUA power problem

How to repear ??
Explane. Thanks

Bought a tcon/main board / PSU from a cracked OLED

Replaced main board and tcon together since it was cheap and was fixed.

Probably only needed to replace one but bought them from same working tv so just replaced both.