JVC KD-G401 Service Manual page 23

5.5 Signal processing section
Is the sound output from
both channels (L, R)?
YES
Normal
1-26 (No.MA051)
NO
No sound from either
channel.
YES
Is 9V present at IC161
pin 31?
YES
Is the audio signal
(including sampling
output components)
output to IC581 pins 1
and 7 during playback?
YES
Is the audio signal
output at IC161 pins 3
and 30 during playback?
YES
Check the power amp.
IC301.
Compare the L-ch and
NO
R-ch to locate the
defective point.
NO
Is 9V present at IC901
pin 10?
YES
Check the connection
between IC901 pin10
and IC301 pin31.
NO
Check IC581 and its
peripheral circuits.
NO
Check IC161 and its
peripheral circuits.
NO
Check IC901 and its
peripheral circuits.