Casio CTK-750, Service Manual

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CIRCUIT DESCRIPTION
Key Matrix
Key
Second contact 2
First contact 1
FI
KC
SI
Note: Each key has two contacts, the first conatct 1 and second contact 2 .
KC0 KC1 KC2 KC3 KC4 KC5 KC6 KC7
FI0 C2 1 C#2 1 D2 1 D#2 1 E2 1 F2 1 F#2 1 G2 1
SI0 C2 2 C#2 2 D2 2 D#2 2 E2 2 F2 2 F#2 2 G2 2
FI1 G#2 1 A2 1 A#2 1 B2 1 C3 1 C#3 1 D3 1 D#3 1
SI1 G#2 2 A2 2 A#2 2 B2 2 C3 2 C#3 2 D3 2 D#3 2
FI2 E3 1 F3 1 F#3 1 G3 1 G#3 1 A3 1 A#3 1 B3 1
SI2 E3 2 F3 2 F#3 2 G3 2 G#3 2 A3 2 A#3 2 B3 2
FI3 C4 1 C#4 1 D4 1 D#4 1 E4 1 F4 1 F#4 1 G4 1
SI3 C4 2 C#4 2 D4 2 D#4 2 E4 2 F4 2 F#4 2 G4 2
FI4 G#4 1 A4 1 A#4 1 B4 1 C5 1 C#5 1 D5 1 D#5 1
SI4 G#4 2 A4 2 A#4 2 B4 2 C5 2 C#5 2 D5 2 D#5 2
FI5 E5 1 F5 1 F#5 1 G5 1 G#5 1 A5 1 A#5 1 B5 1
SI5 E5 2 F5 2 F#5 2 G5 2 G#5 2 A5 2 A#5 2 B5 2
FI6 C6 1 C#6 1 D6 1 D#6 1 E6 1 F6 1 F#6 1 G6 1
SI6 C6 2 C#6 2 D6 2 D#6 2 E6 2 F6 2 F#6 2 G6 2
FI7 G#6 1 A6 1 A#6 1 B6 1 C7 1
SI7 G#6 2 A6 2 A#6 2 B6 2 C7 2