LG DP391B Service Manual page 27

MAIN ELECTRICAL TROUBLESHOOTING GUIDE
B. AUDIO OUT ABNORMAL
Audio out abnormal
YES
Check Audio jack & mode
YES
Check U504
YES
Check signals from MPEG
YES
Replace IC(U504)
D. AUDIO IN/SPEAKER ABNORMAL
Audio in/speaker
abnormal
YES
Check Audio jack &
mode S/W
YES
NO
Is Q510
and Q519 OK.
YES
NO
Is speakers OK.
Replace
YES
Replace IC(U502)
LGE Internal Use Only
Replace
Q510 and Q519
Speakers
3-20
C. VIDEO OUT ABNORMAL
Video out abnormal
YES
Check Video jack & mode
YES
Check Video signals from MPEG
YES
Check IC(U501)
YES
Check LC filter
E. VIDEO IN ABNORMAL
Video in abnormal
YES
Check Video jack
& mode
YES
NO
Is U501 OK.
YES
Check
U701 Pin 14
YES
Refer to LCD part
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Replace
(U501 IC)