Ic600 Abnormal; U654 Abnormal; Ic601 Abnormal - LG SB74 Service Manual

8. IC600 ABNORMAL

Check both end voltage Q600 (3.3V)
Check Q601 is "H"
Check IC604 pin13 is 3.3V
Check IC600 pin1, 6 X601 operation
OK

9. U654 ABNORMAL

Check U654 pin1: CE,
pin6: SCK
YES
OK

10. IC601 ABNORMAL

Check IC601 pin34: CLK
pin35 CKE
YES
OK
YES
YES
YES
YES
NO
Check U654 pin8 VDD 3.3V
Check U654 pin2,5/SO,SI
NO
Check MCU IC603
voltage 1.2V
Check MCU IC603
NO
Refer to power supply no 3.3V,
check or replace Q600
NO Check IC606 pin1 is "H",
Check or replace Q601
NO
Check or replace L600
NO
Check or replace X601
NO
YES
NO
YES
OK
NO
YES
NO
YES
OK
3-5
Refer to 3.3V
troubleshooting
Replace U654
Refer to MCU
troubleshooting
Replace MCU