LG LAB550H Service Manual page 58

ELECTRICAL TROUBLESHOOTING GUIDE
No 5V_USB
YES
Is the
VCC supplied to IC158
pin1?
YES
Is there
signal at IC158
pin3?
YES
Check IC158 and replace.
No 1.2 V, 1.2V_MTK
YES
Is the
VCC supplied to IC153
pin3?
YES
Is there
signal at IC153
pin5?
YES
Check IC153 and replace.
No 1.5V_MTK
YES
Is the
VCC supplied to IC155
pin3?
YES
Check IC155 and replace.
NO
NO
Check IC101 pin24 (P_CTRL1).
NO
NO
Check IC101 pin24 (P_CTRL1).
NO
2-45
Check 5 VA.
Check 12 VA.
Check 3.3 V.