Thank you, I applied 3.3V into pin 13; 23; 10; 24 and I got 22V and all the voltage were correct. So I guess it is not the power board, I'm going to investigate further on the main board tomorrow.

Unfortunately not.

Hello, my name is Kievan, I'm almost 18 and I'm gonna be an electronics engineering student. I repair all sort of thing but I don't have a lot of skills so I'm trying to learn.

Hello, I'm trying to repair an LG OLED65C7V-Z that has no picture and no sound. When I plug the TV, I hear the relay click. When I push the power button, i hear a second click and there are 3 red blinks but no sound and no picture.
I checked the voltage at the power board and I have the 20V and 12V at the mainboard connector, I have the 12V at the T-CON connector but not the 24V.
I tested the power supply without the T-CON and the main board by injecting 3.3V into the PWR_ON pin, the DPC pin and the 12VT_ON pin but still no 24V.
I checked the fuses, the diodes, the capacitors...