(No.49787B)1-29
Signal processing section (new circuit board)
No sound from either
channel.
Is 9V present at IC101 pin
(8)?
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
Q981 audio power
supply.
NO
NONO
NO
YES
YES
YES
YES
YES
Check IC521 and its
peripheral circuits.
Is the audio signal
(including sampling output
components) output to
IC521 pins 50, 53 during
playback?
Is the audio signal output
at IC101 pins 1 and 7
during playback?
NO
Check IC101 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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