LG 55QNED85SQA Service Manual page 48

Standard Repair Process Detail Technical Manual
Error
Established
A. Video error_Video error, video lag/stop
symptom
date
Revised
TUNER checking part
Content A5
date
Checking method:
1. Check the signal strength or check whether the screen is normal when the external device is connected.
2. After measuring each voltage from power supply, finally replace the MAIN BOARD.
A5