CASIO CTK611
Service Manual

Key

Note: Each key has two contacts, the first conatct (1) and second contact (2).
FI Second contact (2) First contact (1) KC SI

NOMENCLATURE OF KEYS
C#2 D#2 F#2 G#2 A#2 C#3 D#3 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 C#6 D#6 F#6 G#6 A#6

C2

D2

E2

F2

G2

A2

B2

C3

D3

E3

F3

G3

A3

B3

C4

D4

E4

F4

G4

A4

B4

C5

D5

E5

F5

G5

A5

B5

C6

D6

E6

F6

G6

A6

B6 C7

POWER SUPPLY CIRCUIT
The power supply circuit generates five voltages as shown in the following table. VDD voltage is always generated. The others are controlled by APO signal from the CPU. Name VDD DVDD AVDD LVDD VCC Voltage +5 V +5 V +5 V +5.6 V +9 V For operation of CPU, Reset IC, DSP, Sound source ROM, Working storage RAM, Effect RAM LCD driver, Power jack, Sustain jack, MIDI jack DAC, Filter LCD dirver Power amplifier, Pilot lamp

RESET CIRCUIT
When batteries are set or an AC adapter is connected, the reset IC provides a low pulse to the CPU. The CPU then initializes its internal circuit, and clears the working storage RAM. When the power switch is pressed, the CPU receives a low pulse of POWER signal. The CPU sends APO signal to the power supply circuit, also sends a reset signal to the DSP.
Battery set VDD Reset signal RESET Reset IC IC1 RN5VD40AA POWER NMI From power switch �5� PLE CPU LSI1 UPD913GF-3BA APO SCKO To power supply circuit DSP LSI2 HG51B277FB-1 VDD VDD

MC-Service