LG MDD105 Service Manual page 25

ONE POINT REPAIR INSTRUCTION
When you turn on the set, it will show 'welcome' message continuously on the front
panel. And it will not boot-up normally.
4-2. IC100 (LC87F5NC8A)
4-2-1. Solution
Replace IC100 on main board.
4-2-2. How to troubleshoot (Countermeasure)
1) If 3.3 V haven't on main board of P1, please check P-SENS 5V come out or not?
Please check D1 or replace D1 on SMPS.
2) If 5V normal, first check R100, R101, R102; OK!
Check the IC101 out and check the zener diode ZD101 voltage if between 4.18 ~ 4.3 V(main pcb).
3) After changging it, the SET is still not booting, please check 5.6 VA at P7904 come out?
Please check or replace diode D3 or L1 on the SMPS board;
Other check the main MCU reset IC U101_KIA7027 of replace it, check or replace D101,D102(main PCB bottom )
4) All of changed the SET still boot-up, please check or replace IC100_LC87F5NC8A(main pcb).
4-2-3. Service hint (Any picture / Remark)
3-10