Read LG 50PT350B-SG (CHASSIS:PB12K) Service Manual online
14. USB Trouble Shooting
• Exception
- USB power could be disabled by inrushing current
- In this case, remove the device and try to reboot the TV (AC power off/on)
Check USB 2.0 Cable
Y
Check JK1102 (Normal)
JK1100 (SVC only)
N
Y
Y
Check USB device
If device is 2.5 inch HDD,
Check power adaptor
Replace Jack
Check 5V voltage level
IC1101 #2 (Normal)
L1100 (SVC only)
N
Replace one of
IC1101, L1100 & Recheck
Y
MaybeMstar S7LR (IC101)
has problems. Replace It.