CASIO CT870 Service Manual

PORTAMENTO

A

L

T

U

I

O

D

N

O

M

B

E

N

W

SLOW FAST

O

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

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

— 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

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 —

CASIO CT870 Service Manual

CT-870

CONTENTS

SPECIFICATIONS

BLOCK DIAGRAM

CIRCUIT DESCRIPTION