GM SOUND KEYBOARD
CTK-680
CTK-680
-- 2 --
CONTENTS
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Major Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Printed Circuit Boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Schematic Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Exploded View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
SPECIFICATIONS
GENERAL
Model:
CASIO CTK-680
Keyboard:
61-key, 5-octave standard size keyboard with touch response (three sensi-
tivity levels and OFF setting)
Tones:
128 tones (Conform with General MIDI level 1) + 8 drum sounds with split/
layer features.
Polyphony:
32 notes maximum
Digital effects:
10
REVERB 1, REVERB 2, REVERB 3, CHORUS, TREMOLO, PHASE
SHIFTER, ORGAN SPEAKER, ENHANCER, FLANGER, LOUDNESS
Musical pads:
120 (four pads
× 30 sets)
Phrases (22 sets), drums/percussion (7 sets), controller (1 set)
Phrases matche chord
Demo tunes:
3, sequential repeat playback
Auto-accompaniment
Rhythm patterns:
100
Tempo:
Adjustable (216 levels,
= 40 to 255)
Chords:
3 types (CASIO Chords, Fingered, Full-Range Chords)
Parts:
Rhythm, bass, Chord 1, Chord 2, Chord 3 (adjustable on/off, tone, volume,
pan, effect send, fine tune, coarse tune, expression settings)
Others:
Intro, Normal Fill-in, Variation Fill-in, Synchro/Ending
Magical presets:
50 types (Break Beat, Melodycomp, Shadow Drum, Free Session)
Registration memory:
10
Tone changes, tempo setting, auto-accompaniment volume setting, mode,
layer on/off, Mixer settings, effect type, split on/off, rhythm type, auto-
accompaniment rhythm assignment, pad type, chord fingering method,
touch response setting, MIDI settings (including assignable jack settings),
Magical Preset type
Mixer
Number of channels:
16
Parameters:
TONE, VOLUME, PAN, EFFECT SEND, FINE TUNE, COARSE TUNE,
EXPRESSION
Multi-track memory
Number of songs:
2
Tracks:
6 (tone, volume, auto accompaniment, magical presets, pan, effect send, fine
tune, coarse tune, expression)
Type:
Real-time
Capacity:
Approximately 5,200 notes
-- 3 --
Other functions
Transpose:
25 levels (1 octave lower C to 1 octave upper C)
Tuning:
Adjustable: A4 = 440 Hz
± 50 cents
Pitch Bender:
Adjustable range:
± 12 semitones (bend up, bend down, bend saw) using
musical pads
Modulation:
Vibrato setting and performances are done by a Musical pad.
MIDI:
16-timbre multi-timbre receive (General MIDI Level 1)
Speakers:
12 cm diameter
× 2 (output: 2.5 W + 2.5 W)
Input/Output Jacks
Power supply:
9 V DC
Headphones:
Stereo mini jack
Output jacks:
Output impedance: 120
Output voltage 4.2 V (RMS) MAX
Assignable Jack:
Standard jack (sustain, sostenuto, soft, rhythm start/stop)
MIDI terminals:
IN, OUT
Power supply:
2-way
Batteries:
Six D-size batteries
Battery life:
Approximately 5 hours on R20P (SUM-1) manganese batteries
AC adaptor:
AD-5 (optional)
Auto power off:
Approximately six minutes after last key operation under battery power
(disabled when AC adaptor is connected).
Power consumption:
9 V --- 7.7 W
Dimensions:
94.2
× 36.7 × 13.5 cm (31-7/16 × 14-1/2 × 4-3/8 inches)
Weight:
5.2 kg (11.7 lbs) excluding batteries
ELECTRICAL
Current drain with 9 V DC:
No sound output
320 mA
± 20%
Maximum volume
with 12 polyphonic notes in tone No. 022
960 mA
± 20%
Volume; maximum
Phone output level (Vrms with 8
load each channel): Left channel 115 mV ± 20%
with key C6 pressed in tone No. 042
Line output level (Vrms with 47 k
load each channel): Left channel 1280 mV ± 20%
with key C5 pressed in tone No. 042
Minimum operating voltage:
5.75 V
-- 4 --
BLOCK DIAGRAM
KC0 ~
KC7
SI0 ~ SI7
FI0 ~ FI7
Key Controller
LSI16
HG52E35P
Working Storage RAM
(256K-bit)
LSI15
TC55257DFL-70L
KO1 ~ KO4, KO8
LED Driver
IC301
BA612
LD0 ~
LD7
Buttons
KI1 ~ KI4
Power Switch
IN
EA0 ~ EA14
ED0 ~ ED7
DSP
IC11
HG51B155FD
RA0 ~ RA20
RD0 ~ RD15
Sound Source ROM
(24M-bit)
LSI12
MX23C2410MC-12CA54
WCK1
SLOP
BCK
D/A Converter
IC11
UPD6376GS
Filter
Q208
Main
Volume
Power Amplifier
IC202
LA4598
CPU
LSI14
HD6433294A33F
Keyboard
A0 ~ A14
NMI
Power Supply Circuit
IC203, Q201 ~ Q206
VCC
AVDD
VDD
LVDD
DVDD
VC
Effect RAM
(256K-bit)
LSI13
LC33832M-70
D0~D7
Speakers
Output
A0 ~
A14
A0 ~ A3
A0 ~ A2
7-seg. LED
LEDs
LED Driver
Q15 ~ Q18
Gate Array
LSI17
UPD65611GB-019
La ~ Lg, Lp
LC1 ~ LC4, LC8
MIDI
OUT
KOC
KOD
CLK
KO0 ~
KO9
Filter
Q207
RES
Reset IC
IC13
RH5VL36AA
-- 5 --
CIRCUIT DESCRIPTION
KEY MATRIX
Note: Each key has two contacts, the first conatct (1) and second contact (2).
Key
Second contact (2)
First contact (1)
FI
KC
SI
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)