CASIO CT870 Service Manual

PORTAMENTO

A

L

T

U

I

O

D

N

O

M

B

E

N

N

W

SLOW FAST

O

D

D

N

E

B

V

O

E

L

M

U

MELODY CONTROLLER

CT-870

MAIN

FULL RANGE

MAX

MIN

CHORD

FINGERED

CASIO
CHORD

MODEPOWER REVERB

HALL

STAGE

ROOM

SAVE

SPLIT LAYER RHYTHM TONE

ACCOMP

TEMPO NORMAL/

VOLUME

VARIATION


INTRO/

SYNCHRO/

START/

FILL-IN

ENDING

STOP

789

456

123

0

| {

⁄ ¢

MULTI FUNCTION DISPLAY

DEMO

TRANSPOSE/
TUNE/MIDI

SONG
MEMORY

TOUCH
RESPONSE

VOLUME

REGISTRATION

456

123

D

U

P

100
TONES

100
RHYTHMS

PIANO

00

PIANO

01

HARD PIANO

02

STUDIO PIANO

03

HONKY-TONK

04

ELEC PIANO 1

05

ELEC PIANO 2

06

ELEC PIANO 3

07

CHORUSED EP

08

HARPSICHORD

09

CLAVELECTRO

CHROMATIC PERC

10

MUSIC BOX

11

VIBRAPHONE

12

MARIMBA

13

THUMB PIANO

ORGAN

14

ELEC ORGAN 1

15

ELEC ORGAN 2

16

ELEC ORGAN 3

17

JAZZ ORGAN

18

ROCK ORGAN 1

POPS I

00

NICE GROOVE

01

POPS 1

02

BALLAD

03

POP BALLAD

04

GROOVE POP

05

RAP POP

06

POP REGGAE

07

SOUL BALLAD

08

POPS 2

09

POP WALTZ

POPS II

10

16 BEAT 1

11

16 BEAT 2

12

16 BEAT 3

13

8 BEAT 1

14

8 BEAT 2

15

8 BEAT 3

16

POPS 3

17

POPS 4

18

POP FUSION

19

LATIN POP

19
20
21
22
23
24

GUITAR/BASS

25
26
27
28
29
30
31
32
33
34
35
36
37
38
39

ROCK I

20
21
22
23
24
25
26
27
28
29

ROCK II

30
31
32
33
34
35
36
37
38
39

ROCK ORGAN 2
CHURCH ORGAN
ACCORDION
BANDONEON
REED ORGAN
HARMONICA

GUT GUITAR
ACOUS GUITAR
JAZZ GUITAR
ELEC GUITAR
MUTE GUITAR
DIST GUITAR
HARP
BANJO
WOOD BASS
ELEC BASS 1
ELEC BASS 2
FRETLESS BASS
SLAP BASS
SYNTH-BASS 1
SYNTH-BASS 2

ROCK WALTZ
SLOW ROCK 1
SLOW ROCK 2
SOFT ROCK 1
SOFT ROCK 2
SOFT ROCK 3
FOLKIE POP
POP ROCK
60's SOUL
FOLK ROCK

ROCK 1
ROCK 2
ROCK 3
RIFF ROCK
HEAVY METAL
50's ROCK
TWIST
N'AWLINS R&R
CHICAGO BLUES
R&B

ORCHESTRA/ENS

40

VIOLIN

41

CELLO

42

PIZZICATO STR

43

TIMPANI

44

ORCHESTRA HIT

45

STRINGS 1

46

STRINGS 2

47

SYNTH-STR 1

48

SYNTH-STR 2

49

CHOIR

50

SYNTH-VOICE

BRASS

51

TRUMPET

52

TROMBONE

53

TUBA

54

MUTE TRUMPET

55

FRENCH HORN

56

BRASS

57

SYNTH-BRASS

REED/PIPE

58

SOPRANO SAX

JAZZ/FUSION

40

BIG BAND

41

SLOW SWING

42

SWING

43

FOX TROT

44

JAZZ WALTZ

45

MODERN JAZZ 1

46

MODERN JAZZ 2

47

ACID JAZZ

48

LATIN FUSION

49

FUSION

DANCE/FUNK

50

TECHNO

51

EURO BEAT

52

TRANCE

53

DISCO 1

54

DISCO 2

55

HOUSE

56

RAP

57

RAVE

58

FUNK 1

59

FUNK 2

59
60
61
62
63
64
65
66
67
68

SYNTH-LEAD

69
70
71
72
73
74
75
76

SYNTH-PAD

77
78

EUROPEAN

60
61
62
63
64
65
66
67
68
69

LATIN I

70
71
72
73
74
75
76
77
78
79

ALTO SAX
TENOR SAX
BARITONE SAX
OBOE
CLARINET
PICCOLO
FLUTE
RECORDER
PAN FLUTE
WHISTLE

SYNTH-LEAD 1
SYNTH-LEAD 2
SYNTH-LEAD 3
CALLIOPE
POWER LEAD
FIFTH LEAD
BASS+LEAD
BOTTLE LEAD

FANTASY
WARM PAD

POLKA 1
POLKA 2
MARCH 1
MARCH 2
SLOW WALTZ
VIENNESE WALTZ
WALTZ
SIRTAKI
SERENADE
TANGO

BOSSA NOVA 1
BOSSA NOVA 2
SAMBA 1
SAMBA 2
JAZZ SAMBA
MAMBO
RHUMBA
CHA-CHA-CHA
MERENGUE
BOLERO

79

SYNTH-ENS

80

SPACE CHORUS

81

GLASS HARMONICA

82

COUNTRY FARM

83

POWER STRINGS

84

DREAM PAD

85

PEARL DROP

86

SOUNDTRACK

87

CRYSTAL

88

ATMOSPHERE

89

COSMIC SOUND

90

SPACE

91

SYNTH-SFX

ORIENTAL

92

ERHU

93

ZHENG

94

YANG QIN

95

DIZI

96

SHENG

PERCUSSION

97

PERCUSSION 1

98

PERCUSSION 2

99

PERCUSSION 3

LATIN II/VARIOUS I

80

REGGAE 1

81

REGGAE 2

82

PUNTA

83

CUMBIA

84

PASODOBLE

85

RUMBA CATALANA

86

SEVILLANA

87

SKA

88

TEX-MEX

89

FOLKLORE

VARIOUS II

90

COUNTRY

91

BLUEGRASS

92

TOWNSHIP

93

SLOW GOSPEL

94

RAI

95

ADANI

96

BALADI

97

ENKA

98

6/4

99

9/8

ELECTRONIC KEYBOARD

CT-870

CONTENTS

Page

Specifications ................................................................................................................................2

Block Diagram............................................................................................................................... 3

Circuit Description ......................................................................................................................... 4

Major Waveforms ........................................................................................................................ 11

Printed Circuit Board ................................................................................................................... 12

Schematic Diagrams ................................................................................................................... 13

Exploded View ............................................................................................................................ 17

Parts List ..................................................................................................................................... 19

SPECIFICATIONS

GENERAL

Number of keys: 61
Polyphonic: 24-note (12 for some tones)
Preset tones: 100, with split/layer functions
Keyboard controls: Touch response: On/Off, Key transpose: 12 steps (F#-C-F)
Auto-rhythms: 100, Tempo control: 40 to 255

Auto-accompaniment: Mode: CASIO Chord/Fingered Chord/Full Range Chord

Controller: Intro/Fill-In, Synchro/Ending, Normal/Variation
Reverb effects: Hall/Stage/Room
Registrations: 6, Parameters registered: Tone No. (Normal, Layer, Split, Layer Split),

Rhythm No., Tempo, Accompaniment volume, Chord type, Reverberation

type, Split/Layer settings, Pitch bend range, Basic channel, Local on/off,

Portamento on/off
Song memory: 1, Real-time recording, Memory capacity: Approx. 1200 notes in total
Demo tunes: 1, including — Mei Wenti (Edward Alstrom)
Tuning control: 440Hz ± 50 cents
Built-in speakers: 12 cm dia. 2.5 W input rating: 2 pcs.
MIDI: 16 multi-channel reception
Terminals: Phone Jack [Output impedance: 110 Ω, Output voltage: 4.2 V(rms)

MAX], Sustain Jack, MIDI Jacks (IN, OUT), AC Adapter Jack (9 V) ,

Foot volume Jack
Auto power off: Approximately 6 minutes after the last operation
Power source: 2-way AC or DC source

AC: AC adapter

DC: 6 D size dry batteries
Power consumption: 7.7 W
Dimensions (HWD): 140 x 997 x 376 mm (5-1/2 x 39-5/16 x 14-13/16 inches)
Weight: 5.4 kg (11.9 lbs) without batteries

— 2 —

BLOCK DIAGRAM

Reset IC

IC106

RE5VA35AA

Sound Source ROM

(16M-bit)

LSI104

MX23C1610PC-

12CA38

Effect RAM

(64K-bit)

LSI105

LC3564S-10

RESET

MA0 ~ MA19

MA0, MA1

EA0 ~
EA12

EIO0 ~
EIO7

Working Storage

RAM (64K-bit)

LSI103

LC3564S-10

MA0

~

MA12

MD0 ~ MD15

MD0

~

MD7

HG51B277FB

DSP

LSI102

SUSTAIN

MIDI

INOUT

CPU

LSI101

UPD913GF-3BA

BCK, SO, LRCK

PA0 ~ PA6

PB0 ~ PB4

Power Switch

VDD

KI0 ~ KI2SI9

Buttons

FI0 ~ FI10
SI0 ~ SI8

KC0 ~ KC7

LED driver

Q401 ~ Q407

LED driver

IC105

BA612

FI9, FI10

Keyboard

La ~ Lg, Lh

LEDs /

7Seg. LED

LC0 ~ LC4

Speakers

Output

LRCK SO BCK

D/A Converter

IC106

UPD6379GR

Filter

Q115 ~ Q118

Main
Volume

Amp.

IC101

M5218APR

Power Amplifier

IC102

LA4598

Foot volume

APO

LVDD

VCC

AVDD

Power Supply Circuit

Q102 ~ Q109

D106, D108, D109

DVDD

VC

VDD

— 3 —

CIRCUIT DESCRIPTION

KEY MATRIX

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)

FI9

FI10

Intro/

Fill-In

Registration5Registration

Synchro/

Ending

6

Portament

Save

Start/

Stop

Normal/

Variation

Registration1Registration2Registration3Registration

4

Tempo

Up

Tempo

Down

Accomp.

Volume

Up

Accomp.

Volume

Down

KI0 Mode Rhythm 0 1 4 7 Layer Split

KI1 Reverb Tone – 2 5 8

Transpose
Tune/MIDI

KI2 +3 6 9

Song

Memory

Demo

Touch

Response

— 4 —

Note: Each key has two contacts,
the first conatct (1) and second contact (2).

NOMENCLATURE OF KEYS

Second contact (2)

Key

First contact (1)

FI

KC

SI

C#2

C2 D2E2F2G2A2 B2 C3 D3

F#2D#2

C#3A#2G#2

F#3 G#3

D#3

E3

F3 G3 A3 B3 C4 D4 E4 F4 G4 A4 B4 C5 D5 E5 F5 G5 A5 B5

A#3 C#4 D#4

F#4 G#4

A#4

C#5

D#5

F#5 G#5

A#5

C#6

C6

G#6F#6D#6

A#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 from the CPU.

Name Voltage For operation of

VDD +5 V CPU, Reset IC, DSP, Sound source ROM, Working storage RAM, Effect RAM

DVDD +5 V Power jack, Sustain jack, MIDI jack
AVDD +5 V DAC, Filter

LVDD +5 V LED Driver

VCC +9 V Power amplifier, Pilot lamp

VC +9 V Power amplifier

B6A6G6F6E6D6

C7

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, then the CPU sends
a reset signal to the DSP.

Battery set

VDD

Reset IC

IC106

RE5VA35AA

POWER

From power switch

RESET

VDD

CPU

LSI101

UPD913GF-3BA

NMI

— 5 —

Reset signal

PLE

HG51B227FB

VDD

DSP

LSI102

CPU (LSI101: UPD913GF-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 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 LSI101.

Pin No. Terminal In/Out Function

1 TXD0 Out MIDI signal output
2 RXD0 In MIDI signal input

3 SCK0 Out APO (Auto Power Off) signal output

4, 5 TXD1, RXD2 — Not used. Connected to ground.

6 SCK1 Out 1 MHz synchronizing pulse output
7 AVCC In +5 V source
8 AN0 In Pitch bend control voltage input

9 AN1 In Modulation control voltage input
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

15, 16 XLT0, XLT1 In/Out 20 MHz clock input/output

17 VCC In +5 V source

18, 19 MD0, MD1 In Mode selection terminal

20 RSTB In Reset signal input
21 NMI In Power ON signal input

22 INT — Not used. Connected to ground.

23 ~ 30
31 ~ 38 KC0 ~ KC7 Out Terminal for key input signal
39 ~ 46

47, 48 FI8, SI8 — Not used

49 FI9 In Terminal for button input signal
50 SI9 In Substain signal input
51 FI10 In Terminal for button input signal
52 SI10 In Not used

53 ~ 55 KI0 ~ KI2 In Terminal for button input signal

56 MWNB Out Write enable signal output

57 ~ 76 MA0 ~ MA17 Out Address bus

77 MCSB0 Out Chip enable signal output for the sound source ROM
78 MCSB1 Out Not used

79 MCSB2 Out Chip enable signal output for the DSP

FI0 ~ FI3
SI0 ~ SI3

FI4 ~ FI7
SI4 ~ SI7

In Terminal for key input signal

In Terminal for key input signal

— 6 —

Pin No. Terminal In/Out Function

80 VCC In +5 V source
81 GND In Ground (0 V) source

82 MRDB Out Read enable signal output

83 ~ 98 MD0 ~ MD15 In/Out Data bus

99 PLE Out Reset signal output for the DSP

100 P17 In APO cancellation signal input

CPU Block Diagram

CE

RAM



LSI103

OE

OE

ROM



LSI104

WE

MWEB
MRDB

CE

MD0 ~ MD7

MA0 ~ MA10

MD0 ~ MD15

MA0 ~ MA19

MCSB0

MA0/MA1

RCEB

MRDB

SCK0

P17

WEB

MWNB

NMI

DSP



LSI102

CE1B

MCSB2

CPU



LSI101

RSTB

RESB

PLE

TXDO

RXDO

SCK1

BCK

SO

LRCK








SI9
AN1
AN0

XLT0/XLT1

Sound data and 
timing signals

MIDI input/output

KC0 ~ KC7

FI0 ~ FI10, SI0 ~ SI7
KI0 ~ KI2

Sustain signal
Modulation

Pitch bend

APO

APO cancel signal

Power ON signal

Reset IC PG 20MHz

— 7 —

DIGITAL SIGNAL PROCESSOR (LSI102: HG51B277FB)

The DSP receives 16-bit serial sound data output 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 contains two I/O
ports, which controls LEDs.
The following table shows the pin functions of LSI102.

Pin No. Terminal In/Out Function

1 ~ 4, 80 PB0 ~ PB4 Out LED drive signal output

5 SO Out Serial sound data output for the DAC
6 WCKO Out Word clock output for the DAC

7 VDD3 In +5 V source
8 TEST — Not used.
9 RESB In Reset signal input

10 VSS2 In Ground (0 V) source

11, 12 XIN, XOUT In/Out 16 MHz clock input/output

13 WCKI In Word clock input from the CPU
14 SI In Serial sound data input from the CPU
15 BCKI In Bit clock input from the CPU
16 SINC In 1 MHz synchronizing pulse input

17 VDD2 In +5 V source

18 ~ 25 IO0 ~ IO7 In/Out Data bus

26 RCEB Out Chip enable signal output for the working storage RAM
27 VSS3 In Ground (0 V) source
28 AD1 In Address bus

29 OEB In Not used. Connected to +5 V source.
30 WEB In Write enable signal input
31 VDD3 In +5 V source
32 CE2 In Chip enable signal input. High active.
33 AD0 In Address bus

34 CE1B In Chip enable signal input. Low active.

35 ~ 41, 43 EIO0 ~ EIO7 In/Out Data bus for the effect RAM

42, 44, 46 ~

48, 51 ~ 57, 59

45 ECEB Out Chip enable signal output for the effect RAM
49 EOEB Out Read enable signal output for the effect RAM

50 VSS3 In Ground (0 V) source
58 EA13 Out Not used
60 EWEB Out Write enable signal output for the effect RAM
61 EA14 Out Not used

62, 66, 70, 74,

78

63, 67, 71, 75,

79

64, 65, 68, 69,

72, 73, 76, 77

EA0 ~ EA12 Out Address bus for the effect RAM

VSS2 In Ground source

VDD2 In +5 V source

PA0 ~ PA7 Out LED segment signal output

— 8 —

DSP Block Diagram

Effect RAM Access

APO

CE2
CE1

WE

OE

ECEB
EWEB
EOEB

RAM

LSI105

EI00 ~ EI07

EA0 ~ EA12 PB0 ~ PB4

DAC (LSI106: UPD6379GR)

LED Driving

LVDD

Q401 ~ Q407
Q120

PA0 ~ PA7

La ~ Lh

DSP

LSI102

IC105

LC0 ~ LC4

LG

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

LSI106

UPD6379GR

SI

Word clock

LRCK

CLK

Data

WCKO

Bit clock

SO

DSP

LSI102

HG51B277FB

SINC

SI

Word clock

WCKI

Bit clock

BCKI

Data

SCK1

SO

LRCK

BCK

CPU

LSI101

UPD913GF-3BA

— 9 —

FILTER BLOCK

Since the sound signals from the DAC are stepped waveforms, the filter block is added to smooth the
waveforms.

AVDD

AVDD

To main volume

10V22µ

2SC1740SQ

2.2 K

C331

1 K

C332

2SC1740SQ

1 K 1 K

C331

1 K

AG

18 K

50 V 0.22 µ

47 K

AG

From the DAC

AG

AG

AG

POWER AMPLIFIER (IC102: LA4598)

The power amplifier is a two-channel amplifier with standby switch.
The following table shows the pin function of IC101.

Pin No. Terminal In/Out Function

1 Power GND In Ground (0 V) source
2 Ch1 B.S. — Terminal for a bootstrap capacitor

3 Ch1 OUT Out Channel 1 output
4 VCC In +9 V source
5 Ch1 N.F. In Negative feedback input
6 Ch1 IN In Channel 1 input
7 D.C. — Terminal for a decoupling capacitor

8 Pre GND In Ground (0 V) source

9 Stand by In Power control signal input. 0 V: Off, +9 V: On
10 Ch2 IN In Channel 2 input
11 Ch2 N.F. In Negative feedback input
12 Ch2 OUT Out Channel 2 output

13 Ch2 B.S. — Terminal for a bootstrap capacitor
14 NC — Not used

— 10 —

MAJOR WAVEFORMS

1

2

3

CH1: CH2:

5 V5 V

1 POWER ON signal

UPD913GF-3BA pin 21

2 APO signal

UPD913GF-3BA pin 3

3 Reset signal for the DSP

UPD913G-3BA pin 99

0.1 s

CH1

CH2

4

5 VCH1:

4 Synchronizing pulse

UPD913GF-3BA pin 6

20 µs

CH1

A

B

C

5 VCH1: 5 VCH2: 5 VCH3:

A Word clock LRCK

UPD913GF-3BA pin 13

B Data signal SO

UPD913GF-3BA pin 12

C Bit clock BCK

UPD913GF-3BA pin 11

2 µs

D

CH1

E

CH2

F

CH3

Note: On

2 µs

CH1

CH2

CH3

5 VCH1: 5 VCH2: 5 VCH3:

D Word clock LRCK

UPD6379GR pin 1

E Data signal SI

UPD6379GR pin 2

F Bit clock CLK

UPD6379GR pin 3

5

6

7

5 VCH1: 5 VCH2: 5 VCH3:

5 Key scan signal KC0

UPD913GF-3BA pin 31

6 Key scan signal KC1

UPD913GF-3BA pin 32

7 Key scan signal KC2

UPD913GF-3BA pin 33

50 µs

CH1

CH2

CH3

8

9

0

5 VCH1: 5 VCH2: 5 VCH3:

8 LED drive signal PB0

HG51B227FB pin 80

9 LED drive signal PB1

HG51B227B pin 1

0 LED drive signal PB2

HG51B227FB pin 2

5 ms

CH1

CH2

CH3

G

H

CH1: . 1 V

~

CH2: . 1 V

G DAC output (R-ch)

UPD6379GR pin 5

H DAC output (L-ch)

UPD6379GR pin 8

1 ms

CH1

1 ms

CH1

I

CH2

CH2

J

~

CH1: 0.5 V

~

CH2: 0.5 V

~

I Pre-amp. output (R-ch)

M5218APR pin 7

J Pre-amp. output (L-ch)

M5218APR pin 1

Tone : Whistle (68)
Key : A4
Touch response : Off
Reverb : Off
Volume : Maximum

— 11 —

Main PCB JCM469-MA1M

PRINTED CIRCUIT BOARD

16

1920

1112134231718

8

9

10

15

14

— 12 —

1567

Main PCB JCM469-MA1M/MA2M

SCHEMATIC DIAGRAMS

18

20

19

17

8 9 10

3

2

4

14 15 16

11 12 13

1

Note:

1. All capacitance values are indicated in "µF"
(p=10-6 µF).

2. All resistance values are indicated in "Ω"
(k=103 Ω, M=106 Ω).

5 6 7

— 13 —

Console PCB JCM469-CN1M

— 14 —

Controller PCBs JCM469-CN2/CN3

— 15 —

Keyboard PCBs JCM617T-KY1M/KY2M

— 16 —

16

7

8

9

9

6

10

13

14

12

11

14

15

R-1

2

1

24

10

23

3

4

5

22

19

17

18

R-2

20

21

R-3

EXPLODED VIEW

— 17 —

PARTS LIST

CT-870

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.

Item Code No. Parts Name Specification Q R

Main PCB

1 6925 4800 Main PCB ass'y M469-MA1.2M M140392*1 1 B
LSI101 2012 3668 LSI, CPU UPD913GF-3BA 1 A
LSI102 2012 0441 LSI, DSP HG51B277FB 1 A

LSI103/105 2012 0700 LSI, RAM LC3564S-10 2 A

LSI104 2012 3661 LSI, ROM MX23C1610PC-12C38 1 A
LSI106 2105 4249 LSI, DAC UPD6379GR 1 A

IC101 2114 1799 IC M5218APR 1 A
IC102 2114 2891 IC LA4598 1 A
IC104 2114 1421 IC PC900V 1 A
IC105 2114 3318 IC BA612 1 A
IC106 2105 3941 IC RE5VL35AA-TZ

Q101, Q106, 2200 4409 Transistor 2SA933SQ-TP-T

Q120

Q102/104 2251 0469 Transistor 2SB1237Q,R-TV6-T 2 A

2220 1387 Transistor 2SC1740SQ-TP-T 10 A

Q108 2253 0357 Transistor 2SD2008Q,R-T105-T
Q111/112 2253 0420 Transistor 2SD1468SR,S-TP-T 2 A
D101/111

D102 2390 0371 Diode DSK10B-BT-T 1 B

D106, D108

D109, D112/113 2360 1646 Zener diode MTZJ5.6CT-77-T 3 B

D116 2360 2079

X101 2590 0203 Ceramic oscillator CSA16.00MX040 1 B
X102 2590 2009 Crystal oscillator HC-49/US20A
J101 3501 7049 Jack HEC2305-01-330
J102 3612 0665 Jack YKB21-5006
J103 3613 0938 Jack HLJ4416-01-3040
J104 3612 0789 Jack YKB21-5010
J105 3501 4816 Jack YKF51-5051 1 B

VR101

2 6925 4810 Console PCB ass'y M469-CN1M M140393*1 1 B

Q401 - Q407 2200 4409 Transistor 2SA933SQ-TP-T 7 B

LED401 2370 1141 LED SL-9352-60 1 B

LED409/410 2370 1190 LED MVR3378S 2 C

3 6925 4820 Controller PCB ass'y M469-CN2.3 M240412*1 1 B

4 6923 6940 PCB ass'y M617T-KY1M M140211*1 1

D501 - D564 2301 0101 Diode 1S2473-T-77-T

5 6923 6950 PCB ass'y M617T-KY2M M140212*1 1

D565 - D622 2301 0101 Diode 1S2473-T-77-T

6 6906 8291 Rubber button M312088-5
7 6922 2680 Rubber button M312082-2
8 6925 4960
9 6923 4980 Rubber button M312122-2

10 6923 4990 Rubber button M312123-2

Notes: Q – Used quantity

2390 1323 Diode RB100A-T32-T

2390 1344
2360 1085 Zener diode HZS6B1LTD-T

2765 1575 Volume EWA-MJ0S10B23

Console PCB

2390 1344 Diode 1SS133T-77-T 37 B

2370 0616 LED LN28RPX-(TT2) 11 C

Controller PCBs

2370 0616 LED LN28RPX-(TT2) 1 C
3502 2180 Stick controller RKJXK1220-9-50K 1 A

Keyboard PCBs

Mechanical Parts

R – Rank

Diode

Zener diode

Rubber button

1SS133T-77-T 6 B

MTZJ4.7AT-77-T 1 B

M312082-4

1
3

1

2

2

1B
1B
1B
1B
1B

1

64

58

1B
1
1
2
3

A
A

A

B

B

A

B
C
B
C

B
B
B
B

— 19 —

Item Code No. Parts Name Specification Q R

11 6925 4970 Rubber button M312125-4 1
12 6925 4980 Rubber button M240099-2
13 6925 4990
14 3831 0413 Speaker KC120FEL
15 6921 5040
16 6925 4920 Display plate M340457-1
17 6922 2860 White key set, CS M340503*2 1
18 6922 2850 White key set, CB M340503*1
19 6922 2750 Black key set, 5-key M111726-2
20 6922 2740 Black key set, 10-key M111726-1
21 6922 2760 Key contact rubber M211704-1
22 6922 2770 Key contact rubber M211705-1
23 6925 2570 Control stick M340475-1
24 6918 1630 Battery cover M311164*1

Accessories

1014 9396 AC adapter (for China only) AD-5CL-SC1(D)
6925 4890 Console sheet (for China only) M140380-1

Rubber button

Slide knob

M240403-1

M311860-1

B
B

1

B

1

B

2

B

1

C

1

A
A

4

A

1

A

2

A

4

A

1

A

1

B

1

1B
1B

Notes: Q – Used quantity

R – Rank

— 20 —

MA0900361A

Sep, 1996