Circuit Description; Key Matrix; First Contact - Casio CDP-120 Service Manual & Parts List

„ KEY MATRIX
„
KC0
FI0 A0
1
SI0 A0
2
FI1 F1
1
SI1 F1
2
FI2 C2#
1
SI2 C2#
2
FI3 A2
1
SI3 A2
2
FI4 F3
1
SI4 F3
2
FI5 C4#
1
SI5 C4#
2
FI6 A4
1
SI6 A4
2
FI7 F5
1
SI7 F5
2
FI8 C6#
1
SI8 C6#
2
FI9 A6
1
SI9
A6
2
FI10 F7
1
SI10 F7
2
Each key has two contacts, the first contact
NOTE: The diagram below illustrates how the contacts work.
Second contact

CIRCUIT DESCRIPTION

KC1 KC2
A0# B0
1 1
A0# B0
2 2
F1# G1
1 1
F1# G1
2 2
D2 D2#
1 1
D2 D2#
2 2
A2# B2
1 1
A2# B2
2 2
F3# G3
1 1
F3# G3
2 2
D4 D4#
1 1
D4 D4#
2 2
A4# B4
1 1
A4# B4
2 2
F5# G5
1 1
F5# G5
2 2
D6 D6#
1 1
D6 D6#
2 2
A6# B6
1 1
A6# B6
2 2
F7# G7
1 1
F7# G7
2 2
1
Key

First contact

 
KC3 KC4
C1 C1#
1 1
C1 C1#
2 2
G1# A1
1 1
G1# A1
2 2
E2 F2
1 1
E2 F2
2 2
C3 C3#
1 1
C3 C3#
2 2
G3# A3
1 1
G3# A3
2 2
E4 F4
1 1
E4 F4
2 2
C5 C5#
1 1
C5 C5#
2 2
G5# A5
1 1
G5# A5
2 2
E6 F6
1 1
E6 F6
2 2
C7 C7#
1 1
C7 C7#
2 2
G7# A7
1 1
G7# A7
2 2
and second contact .
2
FI
KC
SI
– 4 –
CDP-120
KC5 KC6
D1 D1#
1 1
D1 D1#
2 2
A1# B1
1 1
A1# B1
2 2
F2# G2 G2#
1 1
F2# G2 G2#
2 2
D3 D3#
1 1
D3 D3#
2 2
A3# B3
1 1
A3# B3
2 2
F4# G4 G4#
1 1
F4# G4 G4#
2 2
D5 D5#
1 1
D5 D5#
2 2
A5# B5
1 1
A5# B5
2 2
F6# G6 G6#
1 1
F6# G6 G6#
2 2
D7 D7#
1 1
D7 D7#
2 2
A7# B7
1 1
A7# B7
2 2
KC7
E1
1
E1
2
C2
1
C2
2
1
2
E3
1
E3
2
C4
1
C4
2
1
2
E5
1
E5
2
C6
1
C6
2
1
2
E7
1
E7
2
C8
1
C8
2