LG LST-5600A Service Manual page 38

6. AUDIO TROUBLESHOOTING
(3) No SPDIF Out for ATSC
ATSC Audio is OK?
SPDIF pulse is output from R423? Fig.06
SPDIF pulse is output from IC704(4)?
5V is supplied to JA701(2)?
Check JA701 and surroundings.
Fig.06
SPDIF output
Fig.06
SPDIF output
YES
YES
YES
YES
NO
NO
NO
NO
3-34
Go back to symptom #1
Check IC400 and surroundings.
Check IC704 and surroundings.
Check Power Supply Part.