1-28 (No.MA035)
5.7 Signal processing section
No sound from either
channel.
Is 9V present
at IC901 pin 10?
Compare the L-ch and
R-ch to locate the
defective point.
Is the sound output from
both channels (L, R)?
Check the vicinity of the
IC901 audio power
supply.
NO
NONO
NO
YES
YES
YES
YES
YES
Check IC161 and its
peripheral circuits.
Is the audio signal
(including sampling output
components) output to
IC161 pins 3 and 30 during
playback?
Is the audio signal output
at IC301 pins 5 and 21
during playback?
NO
Check IC301 and its
peripheral circuits.
Check the muting circuit.
Normal
w
w
w
.
x
i
a
o
y
u
1
6
3
.
c
o
m
Q
Q
3
7
6
3
1
5
1
5
0
9
9
2
8
9
4
2
9
8
T
E
L
1
3
9
4
2
2
9
6
5
1
3
9
9
2
8
9
4
2
9
8
0
5
1
5
1
3
6
7
3
Q
Q
TEL 13942296513 QQ 376315150 892498299
TEL 13942296513 QQ 376315150 892498299
http://www.xiaoyu163.com
http://www.xiaoyu163.com
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