Electrical Part Troubleshooting Guide; Smps Part Troubles; P-Sens Part Troubles; Section 3. Electrical Part - LG SB74 Service Manual

SECTION 3. ELECTRICAL PART

1. SMPS PART
12V
Is the F901 nomal?
Is the BD901 nomal?
Is the R901 nomal?
Is Vcc(9V~25V) supplied to IC911 pin5?
Is the D952 nomal?
Is the D950 nomal?
Power Line of Main PCB is short
2. P-SENS PART
Does +4V appear
at U301A
YES
Check JK600 pin21
YES
Check IC603 pin58
TROUBLESHOOTING GUIDE
YES
YES
YES
YES
YES
YES
YES
NO
Check U301A
NO
Is the D702 nomal?
NO
Replace the F901 (Use same type Fuse)
NO
Replace the BD901
NO
Replace the R901
NO
Is the D911 nomal?
Check or replace the D911
NO
Replace the D952
NO
Replace the D950
NO
Check D306
NO
Replace the D702
3-1
NO
NO Refer SMPS 12V
Check