LG 65UH625V - No picture, no sound, backlight works - 12V missing at T-Con connector
Hi everyone,
I recently picked up a faulty LG 65UH625V and have been trying to diagnose it. Here are the symptoms and what I have found so far:
Symptoms:
Backlight turns on normally
No picture, no sound
PC recognizes the TV via HDMI as an output device
What I tried:
My first suspicion was the T-Con board. When I disconnected one of the panel flat cables from the T-Con, half the screen showed white and the other half black - which seemed like a classic T-Con contact issue. I attempted the tape trick but it did not seem to work. I have a replacement T-Con on order but it has not arrived yet.
The problem I caused:
While measuring voltages on the T-Con board I accidentally touched something with the red multimeter probe. The backlight flickered off for a few seconds, came back on, and there was a faint burning smell. Since that moment the half-white screen symptom is gone and the voltage at the T-Con power connector dropped from 12V to around 1V.
My measurements so far:
Power supply output at P2501: 12-13V ✅
Voltage at T-Con power connector (P7100): ~1V ❌
Continuity between P2501 12V pin and P7100: no continuity ❌
T-Con fully disconnected, same result: still no 12V at P7100
The power supply seems fine. The problem appears to be on the mainboard (EAX66882503) between the power input and the T-Con connector. I suspect I damaged something when I accidentally shorted a pin.
Does anyone have a schematic or know which components sit on the 12V path to the T-Con connector on this board?
Thanks in advance!
I recently picked up a faulty LG 65UH625V and have been trying to diagnose it. Here are the symptoms and what I have found so far:
Symptoms:
Backlight turns on normally
No picture, no sound
PC recognizes the TV via HDMI as an output device
What I tried:
My first suspicion was the T-Con board. When I disconnected one of the panel flat cables from the T-Con, half the screen showed white and the other half black - which seemed like a classic T-Con contact issue. I attempted the tape trick but it did not seem to work. I have a replacement T-Con on order but it has not arrived yet.
The problem I caused:
While measuring voltages on the T-Con board I accidentally touched something with the red multimeter probe. The backlight flickered off for a few seconds, came back on, and there was a faint burning smell. Since that moment the half-white screen symptom is gone and the voltage at the T-Con power connector dropped from 12V to around 1V.
My measurements so far:
Power supply output at P2501: 12-13V ✅
Voltage at T-Con power connector (P7100): ~1V ❌
Continuity between P2501 12V pin and P7100: no continuity ❌
T-Con fully disconnected, same result: still no 12V at P7100
The power supply seems fine. The problem appears to be on the mainboard (EAX66882503) between the power input and the T-Con connector. I suspect I damaged something when I accidentally shorted a pin.
Does anyone have a schematic or know which components sit on the 12V path to the T-Con connector on this board?
Thanks in advance!
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