Power Supply On Smps Board - LG CJ98 Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

POWER SUPPLY ON SMPS BOARD

No -5 V
Is the
VCC -7 VA supplied to IC953
pin2?
YES
Is there
'H' signal at Q953
Base?
YES
Check or replace Q953, Q957.
Or
check line of MAIN PCB is short or not.
No output AMP gate line
Is the VCC
13 VA supplied to IC952
pin1 to pin3?
YES
Check and replace IC952.
Or
check line of MAIN PCB is short or not.
NO
Is the D959 normal?
Check or replace Q951.
NO
Check P_CTL
from μ-com.
NO
Is the R952 normal?
Check or replace D952, D959.
3-26
NO
YES
NO
YES
Check or replace D959.
Check or replace R952.