Casio CTK-501 Service Manual
CTK-501
100 RHYTHMS
100 SONG BANNK100 TONES
CHORD BOOK TONE
TRANSPOSE/
TUNE/MIDI
ACCOMP
VOLUME
SYNCHRO/
START/
FILL-IN
STOP
SONG BANK
MAIN VOLUME
TONE
RHYTHM
STATUS
TEMPO
MUSICAL INFORMATION SYSTEM
100 SONG BANNK KEYBOARD
MUSICAL INFORMATION SYSTEM
SONG BANK CONTROLLER
POWER/MODE MAIN VOLUME TEMPO
FINGERED
CASIO CHORD
ON
NORMAL
OFF
ELECTRONIC KEYBOARD
FINGERING/PART
LEFT/
ACCOMP
:1 OCTAVE UP
:PEDAL(SUSTAIN)
7
add9
SONG BANK CONTROLLER
STOP
REW
PLAY/
PAUSE
LEFT RIGHT
ON/OFF
FF
Mm
789
M7 dim aug
RHYTHM
SONG BANK
456
sus4 -5
123
CLEAR
0
RIGHT/
MELODY
CTK-501
CONTENTS
Specifications................................................................................................................................... 1
Block Diagram.................................................................................................................................. 2
Circuit Description............................................................................................................................ 3
Adjustment ....................................................................................................................................... 7
Major Waveforms ............................................................................................................................. 8
Printed Circuit Boards ...................................................................................................................... 9
Schematic Diagrams ...................................................................................................................... 11
Exploded View ............................................................................................................................... 16
Parts List ........................................................................................................................................ 17
SPECIFICATIONS
GENERAL
Keyboard: 61 standard-size keys, 5 octaves
Tones: 100
Polyphony: 12 notes maximum (6 for certain tones)
Auto accompaniment
Rhythm patterns: 100
Tempo: Variable (236 steps, = 20 to 255)
Chords: 2 fingering methods (CASIO CHORD, FINGERED)
Rhythm controller: START/STOP, SYNCHRO/FILL-IN
Accomp volume: 0 to 9 (10 steps)
Song bank
Tunes: 100
Controllers: PLAY/PAUSE, STOP, REW, FF, LEFT (ON/OFF), RIGHT (ON/OFF)
Musical information
Name display: TONE, RHYTHM, SONG BANK name/number
Tempo: Tempo value, metronome, synchro standby, beat indicator
Chord: Chord name, Chord form
Fingering: Fingering indcators, parts, pedal
Song bank status: PLAY, PAUSE, REW, FF
Staff: 5 octaves with sharp and flat indications
Keyboard: 5 octaves
MIDI: 5 multi-timbre receive
Other functions
Transpose: 12 steps (–6 semitones to +5 semitones)
Tuning: Variable (A4 = approximately 440 Hz ± 50 cents)
Volume: 0 to 9 (10 steps)
Terminals
MIDI terminals: IN, OUT
Sustain terminal: Standard jack
Phones/Output terminal: Stereo standard jack
Output Impedance: 78 Ω
Output Voltage: 4 V (RMS) MAX
Power supply terminal: 9 V DC
Power supply Dual power supply system
Batteries: Six D-size batteries
Battery life: Approximately 10 hours on manganese batteries
AC adaptor: AD-5
Auto power off: Turns power off approximately six minutes after last key operation. Enabled
under battery power only, can be disabled manually.
Speaker output: 2.0 W + 2.0 W
Power consumption: 9 V --- 7.7 W
Dimensions (HWD): 961 × 381 × 139 mm (37-7/8 × 15-1/16 × 5-1/2 inches)
Weight: Approximately 5.4 kg (11.91 lbs) (without batteries)
ELECTRICAL
Current drain with 9 V DC:
No sound output 120 mA ± 20%
Maximum volume 750 mA ± 20%
with 12 keys C1 to B1 pressed in Synth-Lead 1
Volume: Maximum
Phone output level (Vrms with 8 Ω load each channel):
with key G2 pressed in Synth-Lead 1 78 mV ± 20%
Speaker output level (Vrms with 4 Ω load each channel):
with key G1 pressed in Synth-Lead 1 1250 mV ± 20%
Minimum operating voltage: 6.0 V
— 1 —
— 2 —
CPU
MSM 6755B-17
LSI2
Keyboard
Buttons
LCD
LCD Driver
SED1278F0A
LSI3
Reset IC
IC1
Oscillator
X1, Q1
Power Supply Circuit
Q201 ~ Q203, Q208, D205
Power Amp.
TA8248K
IC201
Filter (L)
Q206
Filter (R)
Q205
Output
VC VCC DVDD
APO
DC + 9V IN
DB4 ~ DB7
MIDI IN
MIDI OUT
COM1 ~ COM16
SEG1 ~ SEG40
RS
R/W
E
KO8 ~
KO12
KI0 ~ KI6
KO0 ~ KO7
MD0 ~ MD7
MA0 ~ MA18
ROM(2M-bit)
LC372100PM-
G48
LSI1
BLOCK DIAGRAM
CIRCUIT DESCRIPTION
KEY MATRIX
KI0 KI1 KI2 KI3 KI4 KI5 KI6 KI7
KO0 C2 G#2 E3 C4 G#4 E5 C6 G#6
KO1 C#2 A2 F3 C#4 A4 F5 C#6 A6
KO2 D2 A#2 F#3 D4 A#4 F#5 D6 A#6
KO3 D#2 B2 G3 D#4 B4 G5 D#6 B6
KO4 E2 C3 G#3 E4 C5 G#5 E6 C7
KO5 F2 C#3 A3 F4 C#5 A5 F6
KO6 F#2 D3 A#3 F#4 D5 A#5 F#6
KO7 G2 D#3 B3 G4 D#5 B5 G6
KO8 —+0
KO9 321
KO10 6 5 4 Rhythm Tone
Tempo
Down
Start/
Stop
Transpose/
Tune/MIDI
KO11 9 8 7 Fingered Normal Off
KO12 FF Right Stop Left REW
Play/
Pause
Tempo
Up
Synchro/
Fill-In
Song
Bank
CASIO
Chord
Volume
Down
Chord
Book
Accomp
NOMENCLATURE OF KEYS
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
Volume
Up
Volume
G#6F#6D#6
A#6
B6A6G6F6E6D6
C7
— 3 —
CPU (LSI2: MSM6755B-17)
The CPU reads sound data from the ROM in accordance with the pressed key and the selected tone; the CPU
can read rhythm data simultaneously when a rhythm pattern is selected. Then it provides the left and the right
channels’ waveforms separately, by converting the data into the waveforms with two built-in DACs. The CPU
also controls key and button input. The following table shows the pin functions of LSI2.
Pin No. Terminal In/Out Function
1 MA14 Out Address bus
2, 3 NCO — Not used
4 ~ 19 MA0 ~ MA13 Out Address bus
13 MRDB Out Read enable signal
17 MCSB — Not used
20 ~ 27 MD0 ~ MD7 In/Out Data bus
28, 29 NC1, NC2 — Not used
30 DGND In Ground (0 V) source
31 DVCC In +5 V source
32, 33 XTLO, XTLI In/Out 20 MHz clock input/output
34 NC3 — Not used
35 RSTB In Reset signal input
36 P24/RXD In MIDI signal input
37 P25/TXD Out MIDI signal output
38 NMI In Power ON signal input. Connected to +5 V.
39 APO Out APO (Auto Power Off) signal output
40 NC4 — Not used
41 REFH Out Terminal for the internal DAC
42, 43 NC5, NC6 — Not used
44 DAOR Out Right channel sound waveform output
45 NC7 — Not used
46 AVdac In +5 V source for the internal DAC
47 DAOL Out Left channel sound waveform output
48 REFL Out Terminal for the internal DAC and ADC
49 AGdac In Ground source for internal DAC
50 AGadc In Ground source for internal ADC
51 ANI In APO cancellation signal
52 AVadc In +5 V source for the internal ADC
53 NC8 — Not used
54 MOD0 In Mode selection terminal. Connected to +5 V.
55, 56 MOD1, MOD2 In Mode selection terminal. Connected to ground.
57 P40 In Pedal signal input
58 ~ 64 KI0/P30 ~ KI7/P36 In Terminals for key/button input signal
65 KI7/P37 — Not used
66 ~ 73 KO0/P50 ~ KO7/P57 Out Terminals for key scan signal
— 4 —
Pin No. Terminal In/Out Function
74 ~ 77 DB4 ~ DB7 Out Data bus for the LCD driver
78 NC9 — Not used
79 LVCC In +5 V source
80 ~ 84 KO8 ~ KO12 Out Terminals for button scan signal
85 ~ 87 P65 ~ P67 — Not used
88 RS Out Control signal for the LCD driver
89 R/W Out Read/Write signal for the LCD driver
90 E Out Chip enable signal for the LCD driver
91 ~ 95 P73 ~ P77 — Not used
96 LGND In Ground source
97, 100 MA18, MA15 Out Address bus
LCD DRIVER (LSI3: SED1278F0A)
The LCD driver can drive a dot matrix LCD having 40 segment and 16 common lines. The LSI contains 240
graphic symbols in the built-in character generator ROM, and stores 80 characters in the built-in display data
RAM. In accordance with command from the CPU, the LSI is capable of displaying up to 16 characters
simultaneously. The following table shows the pin functions of LSI3.
Pin No. Terminal In/Out Function
1 ~ 22,
63 ~ 80
23 VSS — GND (0 V) source
24, 25 OSC1, OSC2 In/Out
26 ~ 30 V1 ~ V5 In Those voltages are used for generating the stepped pulse of
31, 32 LP, XCLS — Not used
33 VDD In DVDD (+5 V) source
34, 35 FR, DO — Not used
36 RS In
37 R/W In Read/Write terminal. High: read, Low: write
38 E In High: enable, the writing is done at fall edge.
39 ~ 42 DB0 ~ DB3 — Not used. Connected to GND (0 V)
43 ~ 46 DB4 ~ DB7 In/Out Data bus
47 ~ 62 COM1 ~ COM16 Out Common signal/output
SEG1 ~ SEG40 Out Segment signal output
Terminals for the built-in clock pulse generator. The external
resistor connected determines the oscillation frequency.
LCD drive voltage input.
the LCD drive signals.
Data/command determination terminal.
High: data, Low: command
Chip enable signal.
Low: disenable
— 5 —
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