3-3
k
D
B
Power board
Audio signal
input/output board
C
A
k
j
a
b
a
n
p
r
f
g
c
d
e
b
c
d
e
h
j
f
g
m
h
Main board
Key board
D
B
E
r
F
72
60
61
62
59
32
22
23
22
29
72
21
31
56
34
28
28
27
27
17
17
19
16
20
54
43
57
26
26
58
18
66
37
63
30
65
24
41
25
25
32
40
39
38
67
36
70
70
37
30
33
42
53
52
10
47
47
47
10
35
64
5
46
50
49
