LG 55UJ634 Series Service Manual page 102

`17Y LED 28Pin Power Board Diagnostic method
1
▶ Check power board voltage.
▶ Fix the LCD MODEL switch to 20V.(Smart JIG)
3
▶ Connect the 28Pin Power Cable connector
to the Muitl Gender JIG 28Pin connector
2
▶ Disconnect the Main Board 28Pin Power Cable connector.
4
▶ When the OK LED(24V,12V) turns on, Power Board is normal.
▶ When the NG LED turns on, the Power Board
can be judged as defective.
A 28 (19/19)