Usb Part - LG SB74 Service Manual

16. USB PART

Turn on the USB
YES
Check "CHECKING"
or "USB" display
YES
Check reading
YES
Playing,
Check audio output
YES
OK
YES
Check Power supply
circuit Q308
NO
Check Power supply YES
circuit Q302
NO
YES
Check F301
NO
Check SMPS power
supply
NO Check connector locking
CN401, CN705
NO Check CN401
pin2_5V
NO Check U703
pin55, 57
Replace Q308
Replace Q302
Replace F301
NO
Check Power supply circuit
NO Check CN705
pin3, 4 (D+, D-)
NO
Check U503 pin3, 4
3-8
Q316 USB+5V
NO
Check MICOM IC603
pin116, 117 (D+, D-)
NO