LG S65T1-S Service Manual page 45

When you turn on your set, it will blank / no message or Welcome on front panel, and it will not boot-up.
2-2. IC156 System 3.3 V (No System 3.3 V)
2-2-1. Solution
Replace IC156 on MAIN board.
2-2-2. How to troubleshoot (Countermeasure)
1) Please check 5.5 VA of IC156 pin3 (VIN).
2) If 5.5 VA is abnormal, please check SMPS 5.5 VA.
3) If 5.5 VA is OK, but 3.3 V is abnormal at the IC156 pin6 (VOUT), replace IC156.
2-2-3. Service hint (Any picture / Remark)
ONE POINT REPAIR GUIDE
< MAIN board top view >
2-30
IC156 IC156