LG LAB550H Service Manual page 47

When you turn on your set, it will display "WELCOME" on front panel, and it will not boot-up normally.
2-6. IC501 (MPEG IC)
2-6-1. Solution
Replace IC501 on MAIN board.
2-6-2. How to troubleshoot (Countermeasure)
1) Please Check 1.2 V of C528 on MAIN board.
Please Check 3.3 V of C509 on MAIN board.
Please Check 1.5 V of C503 on MAIN board.
2) If it doesn't work even though IC153, IC155, IC157 are no problem,
IC501 MT8553 could have problem.
2-6-3. Service hint (Any picture / Remark)
C528 C528
< MAIN board bottom view >
ONE POINT REPAIR GUIDE
C509 C509
2-34
C503 C503
< MAIN board top view >