Casio CTK-680, Service Manual

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KI1 KI2 KI3 KI4
KO0 MODE PAD A PAD B PAD D
KO1 TEMPO UP TEMPO DOWN START/STOP PAD C
KO2 RHYTHM TONE
KO3
MAGICAL
PRESET
LAYER SPLIT
KO4 DEMO
TOUCH
RESPONSE
DIGITAL EFFECT REGISTRATION
KO5
SYNCHRO/
ENDING
VAR/FILL-IN NORMAL/FILL-IN INTRO
KO6 9 8 7 +
KO7 — 4 5 6
KO8
ACCOMP
VOLUME
MULTI-TRACK
MEMORY
TRANSPOSE/
TUNE/MIDI
MIXER
KO9 0 1 2 3
NOMENCLATURE OF KEYS
BUTTON MATRIX
F#3 G#3 A#3 C#4 D#4 F#4 G#4 A#4 C#5 D#5 F#5 G#5 A#5
F3 G3 A3 B3 C4 D4 E4 F4 G4 A4 B4 C5 D5 E5 F5 G5 A5 B5 C6
D#3
C2 D2 E2 F2 G2 A2 B2 C3 D3
E3
B6 A6 G6 F6 E6 D6 C7
C#3 A#2 G#2 F#2 D#2 C#2 A#6 G#6 F#6 D#6 C#6
POWER SUPPLY CIRCUIT
The power supply circuit generates six voltages as shown in the following table. VDD voltage is always
generated. The others are controlled by APO signal output from the CPU.
Name Voltage For operation of
VDD +5.0 V CPU, Reset IC, Working storage RAM, Gate array
DVDD +5.2 V DSP, Key controller, Sound source ROM, Effect RAM
AVDD +5.0 V DAC, Filter
LVDD +5.0 V LED Driver
VCC +12 V Pilot lamp
VC +12 V Power amplifier