Major Waveforms .................................................................................................................................... 11
Parts List ................................................................................................................................................. 21
SPECIFICATIONS
GENERAL
Keyboard:88 full size keys with initial touch response
Polyphony:24 notes maximum
Tones:10 (with layering)
Tuning curves:3 types (preset for each tone)
Digital effects:REVERB
Demo tunes
Number of tunes:10
Titles:1. Grande valse brillante
2. Turkish March
3. One-Eighty
4. Opaque Mist
5. Harmonious blacksmith
6. Dream Sequence
7. Fugue in G minor
8. Moveable Blues
9. Rainbow
10. Ave Maria
Playback:Repeat sequential play of all tunes; playback always starts from begin-
ning of tune
Manual memory
Type:Real-time recording and playback
Number of songs:2 (SONG A, SONG B)
Capacity:Approximately 1,200 notes (SONG A + SONG B)
Back-up:Power supplied by batteries or AC adaptor
Pedal:Damper
Other featuresTranspose (±1 octave, semitone steps)
Tuning (adjustable, A4 = 440 Hz ± 50 cents)
MIDI:8-channel multi-timbre reception
Speakers:14 cm × 2 (6 W + 6 W)
Terminals:PHONES (standard stereo jack × 1)
LINE OUT (standard mono jack × 2)
Output impedance: 1.0 KΩ
Output voltage: 1.5 V (RMS) MAX
LINE IN (standard mono jack × 2)
Input impedance: 47 KΩ
Sensitivity: 200 mV
MIDI OUT/IN (DIN jack × 2)
— 1 —
DAMPER PEDAL (standard mono jack × 1)
DC 12 V (DC jack × 1)
Power supplyDual power supply system
Batteries:6 D-size batteries
Battery life:Approximately 4 hours on manganese batteries
AC adaptor:AD-12
Auto power off:Turns power off approximately 5 minutes after last key operation.
Enabled under battery power only, can be disabled manually.
Power consumption:18 W
Dimensions (HWD):100 × 1372 × 414 mm (without stand)
(3-15/16 × 54-1/16 × 16-5/16 inches)
Weight:Without stand and excluding batteries 16.8 kg (37.1 lbs)
ELECTRICAL
Current drain with 12 V DC:
No sound output240 mA ± 20 %
Maximum volume
with 24 keys from C1 to B2 pressed in Jazz organ tone2050 mA ± 20 %
Volume: maximum, Touch response: maximum
Phone output level (Vrms with 8 Ω load each channel):
with key E3 pressed in Jazz organ toneL-ch60 mV ± 20 %
R-ch65 mV ± 20 %
Speaker output level (Vrms with 4 Ω load each channel):
with key E3 pressed in Jazz organ toneL-ch860 mV ± 20 %
R-ch920 mV ± 20 %
Lineout output level (Vrms with 47 kΩ load each channel):
with key B5 pressed in Jazz organ toneL-ch140 mV ± 20%
The power supply circuit generates five voltages as shown in the following table. VDD voltage is always
generated. The others are controlled by POWER signal from the CPU.
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 level signal. The CPU sends POWER signal
to the power supply circuit, also sends a reset signal to the DSP.
When the keyboard is powered by batteries and no operation is made for six minutes, CPU drops signal
POWER to shut all the voltage except VDD off.
VDD
Power switch
Battery set
RESET
Reset IC
IC1
RN5VD35AA
NMI
CPU
LSI4
GT913F
VDD
Reset signal
PLE
HG51B277FB
POWER
SCKO
To power supply circuit
VDD
DSP
LSI1
— 5 —
CPU (LSI4: GT913F)
The 16-bit CPU contains a 1k-byte RAM, three 8-bit I/O ports, two timers, a key controller 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 reads sound data and velocity data from the sound source ROM in accordance with
the selected tone; the CPU can read rhythm data simultaneously when a rhythm pattern is selected. Then the
CPU provides 16-bit serial sound data to the DSP. The CPU also controls MIDI input/output and stores
sequencer data into the working storage RAM.
The following table shows the pin functions of LSI4.
The DSP receives 16-bit serial sound data from the CPU and adds the selected effect to the sound data using
the effect RAM. Then the DSP provides the sound data to the DAC. The DSP also drives LEDs.
The following table shows the pin functions of LSI1.
The DAC receives 16-bit serial data output from the DSP. The data contains digital sound data of the
melody, chord, bass, and percussion for the right and left channels. The DAC converts the data into
analog waveforms and output them to each channel separately.
Synch signal
L OUT
R OUT
DAC
LSI6
UPD6379GR
SI
Word clock
LRCK
CLK
Data
WCKO
Bit clock
SO
DSP
LSI1
HG51B277FB
SINC
SI
Word clock
WCKI
Bit clock
BCKI
Data
SCK1
SO
LRCK
BCK
CPU
LSI4
GT913F
FILTER BLOCK
Since the sound signals from the DAC are stepped waveforms, the filter block is added to smooth the
waveforms.
— 8 —
POWER AMPLIFIER (IC101 : LA4620)
The power amplifier is a two-channel amplifier with standby switch.
IN11+
IN11–
IN12–
PriGND
IN21+
IN21–
IN22–
+
3
5
4
6
9
7
8
Input
Amp.
–
–
Input
Amp.
+
Terminal
Protection
Circuit
+
Input
Amp.
–
–
Input
Amp.
+
Pre-drive
Amp.
Pre-drive
Amp.
Pre-drive
Amp.
Pre-drive
Amp.
RL Short
Protector
Ripple
Filter
RL Short
Protector
162101113
NCDCMUTEADJ
Power
Amp.
Power
Amp.
Power
Amp.
Power
Amp.
VCC2
Pop Noise
Prevention
Circuit
19
20
22
23
18
17
15
14
12
21
1
Boot11
OUT11
PoGND1
OUT12
Boot12
VCC1
Boot21
OUT21
PoGND2
OUT22
Boot22
— 9 —
1
MAJOR WAVEFORMS
3
5
4
2
Power ON
1 ADP (POWER) signal
JE connector pin 5
2 NMI signal
JE connector pin 7
7
3 KC0 signal
JD connector pin 15
4 KC1 signal
JD connector pin 14
9
6
5 CE (MCSBO) signal
LSI3 pin 12
6 OE (MRDB) signal
LSI3 pin 14
8
7 DAC output (L-ch)
JE connector pin 12
8 DAC output (R-ch)
JE connector pin13
Tone : Strings
Key : A4
Reverb : ON
Volume : Maximum
Touch response : Maximum
0
9 Sound signal (L-ch)
JF connector pin 7
0 Sound signal (R-ch)
JF connector pin 8
— 11 —
PRINTED CIRCUIT BOARDS
Main PCB JCM423-MA1MSub PCBs JCM423-MA2M/MA3M/MA4M
8
7
2
1
3
4
Top View
6
5
Bottom View
Top View
910
— 12 —
Main PCB JCM423-MA1M
SCHEMATIC DIAGRAMS
87
12
65
3
4
— 13 —
Sub PCBs JCM423-MA2M/MA3M/MA4M
— 14 —
10
9
Console PCBs JCM423-CN1M/CN2/CN3M
— 15 —
Keyboard PCB JCM886T-KY1M
— 16 —
Keyboard PCB JCM886T-KY2M
— 17 —
Keyboard PCB JCM886T-KY3M
— 18 —
27
EXPLODED VIEW
16
R-1
23
22
21
25
3
24
4
29
26
15
13
12
10
11
9
22
23
2
5
14
17
18
19
R-3
20
R-4
6
7
8
1
28
R-2
— 19 —
SP-2
35
33
35
31
34
30
32
— 20 —
PARTS LIST
CPS-85
Notes:This parts list does not include the cosmetic parts, which
parts are marked with item No. "R-X" in the exploded
view.
Contact our spare parts department if you need these
parts for refurbish.
1.Prices and specifications are subject to change without prior notice.
2.As for spare parts order and supply, refer to the
"GUIDEBOOK for Spare parts Supply", published
seperately.
3.The numbers in item column correspond to the same
numbers in drawing.