Electrical Troubleshooting Guide; Power(Smps) Circuit - LG LSS-3200A Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

1. Power(SMPS) CIRCUIT

(1) No 3.7VA
NO 3.7VA.
YES
NO
Is the F101 normal?
YES
NO
Is the BD101
normal?
YES
NO
Is the TH01
normal?
YES
NO
Is Vcc(14~22V) sup-
plied to IC101 Pin3?
YES
NO
Are the D121/D122
normal?
YES
NO
Is there about 2.5V
at the IC103 Pin1?
YES
NO
Is the D124
normal?
YES
NO
Is the D125
normal?
YES
NO
Is the D129
normal?
YES
NO
Is the D126
normal?
YES
Replace the F101.
(Use the same Fuse)
Replace the
BD101.
Replace the TH01.
Is the D102
normal?
NO
Check or Replace
the D102.
Replace the
D121/D122.
Replace the D103.
Replace the
D124.
Replace the
D125.
Replace the
D129.
Replace the
D126.
YES
Is the D127
normal?
YES
Power in Main PCB is
short?
(2) No 24VA
NO 24VA.
YES
Is there about 26V
at the IC151 Pin1?
YES
Check or Replace
the IC151.
(3) No VFD
NO VFD
YES
Is the F102
Normal?
YES
Is the D128
Normal?
YES
Is the ZD151
Normal?
YES
Check or Replace
the D127.
3-5
NO
Replace the
D127.
NO
Check or Replace
the D129.
NO
Check or Replace
the F102.
NO
Check or Replace
the D128.
NO
Check or Replace
the ZD151.