3-3
D
B
Power board
Audio signal
input/output board
C
A
k
j
a
p
n
f
g
b
c
d
e
j
f
g
m
h
Main board
Key board
D
ard
k
r
i
r
q
q
21
63
64
65
62
31
21
22
21
28
20
30
59
27
27
26
26
18
15
19
57
42
60
25
8
61
17
66
29
68
23
40
24
24
31
37
38
39
70
50
50
71
29
45
46
69
36
41
34
21
33
32
16
44
10
44
44
43
67
9
14
49 16
46
46