1-26 (No.MA118)
5.5 Signal processing section
No sound from either
channel.
Is 9V present at IC301 pin
31?
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
Q321 audio power
supply.
NO
NONO
NO
YES
YES
YES
YES
YES
Check IC151 and its
peripheral circuits.
Is the audio signal
(including sampling output
components) output to
IC151 pins 1 and 7 during
playback?
Is the audio signal output
at IC301 pins 3 and 30
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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