CASIO CPS7 Service Manual
CPS-7
(with price)
ELECTRONIC KEYBOARD
CPS-7
CONTENTS
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Major Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
PCB View and Check Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Schematic Diagrams. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Exploded View. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
SPECIFICATIONS
GENERAL
Number of keys: 76
Polyphonic: 24-note
Preset tones: 5, Piano-1, Piano-2, Electric Piano, Pipe Organ, Strings
Layer
Touch response: On/Off
Key transpose: Range of ± 1 octave by a semitone increment
Demo tunes: 5, 1. Petit Chien
2. Cozy's Castle
3. Red Leaves
4. Toccata & Chorus
5. Rainbow
Tuning control: 440Hz ± 50 cents
Built-In speakers: 12 cm dia. 5 W input rating: 2 pcs.
MIDI: 8-channel, multi-timbral reception
Terminals: Phone Jack [Output impedance: 47 Ω, Output voltage: 2.6 V(rms) MAX],
MIDI Jacks (IN, OUT), Sustain Jack, AC Adaptor Jack (12 V)
Auto power off: Approximately 6 minutes after the last operation
Power source: 2-way AC or DC source
AC: AC adaptor AD-12
DC: 6 D size dry batteries
Battery life: approx. 4 hours by manganese batteries R20P/SUM-1
Power consumption: 18 W
Dimensions (HWD): 96 x 1161 x 303 mm (3-3/4 x 45-11/16 x 11-15/16 inches)
Weight: 6.3 kg (13.9 lbs) excluding batteries
ELECTRICAL
Current Drain with 12 V DC:
No Sound Output 145 mA ± 20%
Maximum Volume 1470 mA ± 20%
with keys C2 to B3 (24 polyphonic) pressed in Strings tone
Volume: maximum, Touch response: maximum
Headphone Output Level (Vrms with 8 Ω load each channel):
with key F3 pressed in Strings tone Left channel 100 mV ± 20%
Speaker Output Level (Vrms with 8 Ω load each channel):
with key F2 pressed in Strings tone Left channel 2800 mV ± 20%
Minimum Operating Voltage: 5.8 V
— 2 —
BLOCK DIAGRAM
Sound Source ROM
(2M-bit)
LSI102
TC534200CF-C116
Reset IC
IC106
RE5VA35AA
MIDI
VCC
AVDD
VC
Power Supply Circuit
Q102 ~ Q107,
D105, D106
RESET
IN
OUT
VDD
MD0 ~ MD15
MA0 ~ MA17
APO
CPU
LSI101
UPD912GF-3BA
LRCK, SO, BCK
D/A Converter
IC105
UPD6379GR
Filter
IC104
M5218APR
Main
Volume
KI0
NMI
FI0 ~ FI9
SI0 ~ SI9
KC0 ~ KC7
Buttons
Keyboard
VDD
Power Switch
NOMENCLATURE OF KEYS
F#1 G#1 A#1
E1 F1 G1 A1 B1
C#2
C2 D2E2F2G2A2 B2 C3 D3
F#2D#2
C#3A#2G#2
D#3
E3
Equalizer
IC103
M5218APR
Power Amplifier
IC101
LA4620
F#3 G#3
A#3 C#4 D#4
F3 G3 A3 B3 C4 D4 E4 F4 G4 A4 B4 C5 D5 E5 F5 G5 A5 B5
F#4 G#4
C#5
A#4
D#5
F#5 G#5
A#5
— 3 —
Output
Speakers
C#6
C6
G#6F#6D#6
A#6
B6A6G6F6E6D6
C#7 D#7 F#7
C7
D7 E7 F7 G7
CIRCUIT DESCRIPTION
KEY MATRIX
KC0 KC1 KC2 KC3 KC4 KC5 KC6 KC7
FI0 E1 (1) F1 (1) F#1 (1) G1 (1) G#1 (1) A1 (1) A#1 (1)
SI0 E1 (2) F1 (2) F#1 (2) G1 (2) G#1 (2) A1 (2) A#1 (2)
FI1 B1 (1) C2 (1) C#2 (1) D2 (1) D#2 (1) E2 (1) F2 (1) F#2 (1)
SI1 B1 (2) C2 (2) C#2 (2) D2 (2) D#2 (2) E2 (2) F2 (2) F#2 (2)
FI2 G2 (1) G#2 (1) A2 (1) A#2 (1) B2 (1) C3 (1) C#3 (1) D3 (1)
SI2 G2 (2) G#2 (2) A2 (2) A#2 (2) B2 (2) C3 (2) C#3 (2) D3 (2)
FI3 D#3 (1) E3 (1) F3 (1) F#3 (1) G3 (1) G#3 (1) A3 (1) A#3 (1)
SI3 D#3 (2) E3 (2) F3 (2) F#3 (2) G3 (2) G#3 (2) A3 (2) A#3 (2)
FI4 B3 (1) C4 (1) C#4 (1) D4 (1) D#4 (1) E4 (1) F4 (1) F#4 (1)
SI4 B3 (2) C4 (2) C#4 (2) D4 (2) D#4 (2) E4 (2) F4 (2) F#4 (2)
FI5 G4 (1) G#4 (1) A4 (1) A#4 (1) B4 (1) C5 (1) C#5 (1) D5 (1)
SI5 G4 (2) G#4 (2) A4 (2) A#4 (2) B4 (2) C5 (2) C#5 (2) D5 (2)
FI6 D#5 (1) E5 (1) F5 (1) F#5 (1) G5 (1) G#5 (1) A5 (1) A#5 (1)
SI6 D#5 (2) E5 (2) F5 (2) F#5 (2) G5 (2) G#5 (2) A5 (2) A#5 (2)
FI7 B5 (1) C6 (1) C#6 (1) D6 (1) D#6 (1) E6 (1) F6 (1) F#6 (1)
SI7 B5 (2) C6 (2) C#6 (2) D6 (2) D#6 (2) E6 (2) F6 (2) F#6 (2)
FI8 G6 (1) G#6 (1) A6 (1) A#6 (1) B6 (1) C7 (1) C#7 (1) D7 (1)
SI8 G6 (2) G#6 (2) A6 (2) A#6 (2) B6 (2) C7 (2) C#7 (2) D7 (2)
FI9 D#7 (1) E7 (1) F7 (1) F#7 (1)
G7 (1)
SI9 D#7 (2) E7 (2) F7 (2) F#7 (2) G7 (2)
KI1
Touch
Response
Transpose
/Tune/MIDI
Piano-1 Piano-2 E.Piano
Pipe
Organ
Strings Demo
Note: Each key has two contacts, the first conatct (1) and second contact (2).
Key
FI
Second contact (2)
First contact (1)
KC
SI
— 4 —
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.
When the power switch is pressed, the CPU receives a low pulse of POWER signal.The CPU raises APO
signal to +5 V to turn power on.
VDD
CPU
LSI101
SCKO
POWER
APO
From power switchNMI
Power Supply Circuit
VDD
Battery set
RESET
Reset IC
IC106
RE5VA35AA
RSTB
UPD912GF-3BA
POWER SUPPLY CIRCUIT
The power supply circuit generates four voltages as shown in the following table. VDD voltage is always
generated. The others are controlled by APO signal from the CPU.
Name Voltage For operation of
VDD +5 V CPU, Reset IC, Sound source ROM
AVDD +5.3 V DAC
AVCC +12 V Filter block, Equalizer block
VC +12 V Power amplifier
CPU (LSI101: UPD912GF-3BA)
The 16-bit CPU contains a 1k-byte RAM, three 8-bit I/O ports, two timers, a keycontroller and serial interfaces.
The CPU detects key velocity by counting the time between first-key input signal FI and second-key SI from
the keyboard. The CPU read sound data and velocity data from the sound source ROM in accordance with
the selected tone. Then the CPU provides 16-bit serial sound data to the DAC.The CPU also controls MIDI
input/output and LED driving.
The following table shows the pin functions of LSI101.
Pin No. Terminal In/Out Function
1 TXD0 Out MIDI signal input
2 RXD0 In MIDI signal output
3 SCK0 Out APO (Auto Power Off) signal output
4 ~ 6 — Not used. Connected to ground.
7 AVCC In Ground (0 V) source
8, 9 AN0, AN1 — Not used. Connected to ground.
10 AGND In Ground (0 V) source
11 BCK Out Bit clock output
12 SO Out Serial sound data output
13 LRCK Out Word clock output
14 GND In Ground (0 V) source
— 5 —
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