LG MAX220UB Service Manual page 19

5A
"FILE CHECK" Display?
YES
Checked the CD
DSP GND?
YES
Checked the USB
interface IC reset?
YES
Checked the
DSP X-tal?
YES
Checked the
DSP control?
YES
OK
5B
USB no sound?
YES
Checked the CD
DSP signal out?
YES
OK
NO
IC501(4, 5, 7, 9, 12, 44, 49, 51, 74, 77, 81,
NO
NO
NO
NO
2-10
102, 104, 116, 117)
IC401(42), R425
X502
IC401(26, 27, 28, 60)
IC501(52, 53)