Casio CTK-541 User Manual

CTK-541

INDEX

JULY.1999

E
E
E

CTK-541

ELECTRONIC KEYBOARD

CONTENTS

Specifications ................................................................................................................................... 1

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

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

Adjustment ....................................................................................................................................... 8

Major Waveforms ........................................................................................................................... 10

Printed Circuit Boards .................................................................................................................... 11

Schematic Diagrams ...................................................................................................................... 15

Exploded View ............................................................................................................................... 19

Parts List ........................................................................................................................................ 20

SPECIFICATIONS

GENERAL

Keyboard: 61 standard-size keys, 5 octaves (with touch response on/off)
Tones: 100
Polyphony: 16 notes maximum (8 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 (ACCOMP), RIGHT ON/

OFF (MELODY)

Display

Name display: TONE, RHYTHM, SONG BANK name/number, keyboard settings name/value
Tempo: Tempo value, metronome, synchro standby, beat indicator
Chord: Chord name, Chord form
Fingering: Fingering indicators, 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: 50 Ω
Output Voltage: 3.5 V (RMS) MAX

Power supply terminal: 9 V DC
Power supply DC 9 V

Batteries: 6 D-size batteries

Battery life: Approximately 5 hours on manganese batteries

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 × 376 × 143 mm (37-7/8 × 14-13/16 × 5-5/8 inches)

Weight: Approximately 5.7 kg (12.6 lbs) (without batteries)

— 1 —

ELECTRICAL

Current drain with 9 V DC: Nominal Limit

No sound output 330 mA 330 mA ± 20%
Maximum volume 990 mA 990 mA ± 20%

with 16 keys C1 to D3 pressed in Synth-Lead 1
Volume: Maximum, Touch response: ON(Velocity MAX)

Phone output level (Vrms with 8 Ω load each channel): L 240mV 240 mV ± 20%

with key C3 pressed in Synth-Lead 1 R 250mV 250 mV ± 20%

Speaker output level (Vrms with 4 Ω load each channel):

with key G1 pressed in Synth-Lead 1 L/R 2500mV 2500 mV ± 20%

Output level (Vrms with 47 KΩ load each channel): L 2300mV 2300 mV ± 20%

with key C2 pressed in Synth-Lead 1 R 2400mV 2400 mV ± 20%

Minimum operating voltage: 6.3V 7.0V

— 2 —

— 3 —

CPU

GT913F(T)

LSI1

Keyboard

Buttons

LCD

LCD Driver

KS0066U-10B

LSI3

Reset IC

UPD6379GR-E1

IC1

Oscillator

X1, Q1

Power Supply Circuit

Q201 ~ Q203, Q207, Q208, D205

Power Amp.

TA8248K

IC201

Filter (L)

Q206

Filter (R)

Q205

Phone/Output

VC VCC DVDD

AVDD

APO

DC + 9V IN

DB4 ~ DB7

MIDI IN
MIDI OUT

COM1 ~ COM16

SEG1 ~ SEG40

RS
R/W
E

KI0,KI1
FI8~FI10

FI0 ~ FI7

KC0 ~ KC7

MD0 ~ MD15

MA0 ~ MA19

ROM(8M-bit)

MSM538002E-

N8GS - KDR1

LSI2

Power Switch

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

Volume

Accomp

Volume

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

Up

G#6F#6D#6

A#6

B6A6G6F6E6D6

C7

— 4 —

CPU (LSI1: GT-913F)

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 LSI1.

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

6 SCK1 Out 1 MHZ synchronizing pulse output
7 AVCC In CVDD (+5 V) source

8 AN0 In +5 V when the keyboard is powered by batteries and becomes 0 V

9 AN1 In Input from pitch bender
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 30 MHz clock input/output

17 VCC In +5 V source

18, 19 MOD0, MOD1 In Mode selection terminal

20 RSTB In Reset signal input
21 NMI In Power ON signal input
22 INT/P10 In/Out Data bus for the LCD driver

TXD/P13,

RXD/P14

In/Out Data bus for the LCD driver

AC adaptor detection terminal.

to cancel the APO function when AC adaptor is connected.

23 ~ 30
31 ~ 38 KC0 ~ KC7 Out Terminal for key scan signal
39 ~ 50

51 FI10 In Terminal for button input signal
52 SI10/P23 Out Chip enable signal for the LCD driver

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

56 MWNB Out Write enable signal for the DSP

57 ~ 76 MA0 ~ MA19 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 ~ FI9

SI4 ~ SI9

In Terminal for key input signal

In Terminal for key input signal

— 5 —

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 for the sound source ROM

83 ~ 98 MD0 ~ MD15 In/Out Data bus

99 PLE Out Reset signal output for the DSP

100 P17 In/Out Data bus for the LCD driver

LCD DRIVER (LSI3: KS0066U-10B)

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 KS0066U-10B.

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

— 6 —

FILTER BLOCK

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

Amp.

TA8248K

Filter

Block

POWER AMPLIFIER (IC201: TA8248K)

The power amplifier is a two-channel amplifier with standby switch.
The following table shows the pin function of IC201.

Pin No. Terminal In/Out Function

1 NC — Not used

2 B.S.2 — Terminal for a bootstrap capacitor

3 OUT2 Out Channel 2 output

4 VCC In +9 V source

5 OUT1 Out Channel 1 output

6 B.S.1 — Terminal for a bootstrap capacitor

7 Power GND In Ground (0 V) source

8 Stand by In Power control signal input. 0 V: Off, +9 V: On

9 DC — Terminal for a decoupling capacitor
10 NF1 In Negative feedback input
11 IN1 In Channel 1 input
12 IN2 In Channel 2 input
13 NF2 In Negative feedback input

14, 15 Pre GND In Ground (0 V) source

CPU

MSM6755B-17

— 7 —

MAIN PCB

1) Items to be adjusted:

ADJUSTMENT

Item

Vop voltage setting Voltmeter

2) Adjustment and Test Point Locations

Measuring Instrument

(TOP VIEW)

(BOTTOM VIEW)

Test point

VR1

— 8 —

3) Equipment connection/Procedure

Vop voltage setting

Set Voltmeter

Output
CP3-CP4

Input
Connection

50°

LCD

Input
Point

Eye

Input
Signal

Adjust

Output
Connection

VR1 Voltmeter CP3-CP4

Output
Point

Adjust for

Adjust for 3.90 ~ 4.00V read­ing on voltmeter under the
temparature 20 ~ 25 °C.
Make fine adjustment accord­ing to the following instruc­tion.

Watching the LCD at a 50° angle to the horizontal, adjust Vop
voltage so that unenergized segments are seen dimly.

— 9 —

MAJOR WAVEFORMS

1

1 Clock pulse

GT913F(T) pin 15

4

5

2

3

2 Power source CVDD

JD connector pin 13

3 APO signal

JD connector pin 12

6

7

4 Sound waveform (R-ch) Tone: Whistle (59)

JD connector pin 6 Key: A4

5 Sound waveform (L-ch) Volume: Max.

JD connector pin 5

8

9

8 LCD common signal COM6

KS0066U-10B pin 52

9 LCD common signal COM7

KS0066U-10B pin 53

6 JB connector pin 1
7 JB connector pin 2

— 10 —

PRINTED CIRCUIT BOARDS

Main PCB JCM456-MA1M

1 7 8

6

5
4

3
2

Main PCB JCM456-MA1M

Top View

6

Bottom View

— 11 —

Sub PCB JCM453-MA2M

Sub PCB JCM453-MA2M

Top View

Bottom View

— 12 —

Console PCB JCM453-CN1

Console PCB JCM453-CN1

Top View

Bottom View

— 13 —

Keyboard PCB JCM618T-KY1M

Keyboard PCB JCM618T-KY1M

Top View

Keyboard PCB JCM618T-KY2M

Keyboard PCB JCM618T-KY2M

Bottom View

Top View

Bottom View

— 14 —

Main PCB JCM456-MA1M

SCHEMATIC DIAGRAMS

5

3

2

4

8

9

6

1

7

— 15 —

Sub PCB KDM453-MA2M

— 16 —

Console PCBs JCM453-CN1

— 17 —

Keyboard PCBs JCM618T-KY1M / KY2M

— 18 —

22

33

14

15

29

28

26

27

24

25

30

23

14

15

37

16

3

7

6

9

8

13

34

5

4

12

38

4

20

20

19

21

18

35

21

17

2

1

´

9

3´8

´

10

´

18

R-4

R-4

R-1

15

34

31

36

32

R-5

R-3

R-2

10

10

34

34

11

37

EXPLODED VIEW

— 19 —

PARTS LIST

CTK-541

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.

— 20 —

PARTS PRICE LIST

CTK-541

N Item Code No. Part Name Specification Q PRICE CODE R

Main PCB

N 1 6928 2120 PCB/ASSY (MA1M) M241173*1 1 DE B

D1-D4 2775 2079 DIODE/CHIP DA227TL 4 AA C

LSI1 2012 5005 LSI GT913F(T) 1 BO A

N LSI2 2012 6501 LSI/MC MSM538002E-S1GS-KDR1 1 AV A

LSI3 2012 5935 LSI/LCD DRIVER KS0066U-10B 1 AV A

IC1 2105 4746 LSI UPD6379GR-E1 1 AO B
IC2 2012 1883 IC/MOS RN5VD40AA-TR 1 AE B

Q1,Q2 2253 0308 TRANSISTOR 2SD1119-R(TX) 2 AC B

Q3 2250 1169 TRANSISTOR 2SA1576AT106R 1 AA B

Q4,Q7,Q8,Q11 2252 0637 TRANSISTOR 2SC4081T106R 4 AA B

VR1 2775 0994 POTENTIOMETER EVND8AA03B53 1 AA B

X1 2590 2774 OSCILLATOR/CERAMIC CSACV30.00MXJ040 1 AE B

SUB PCB ASS'Y

2 6927 3690 PCB/ASSY (MA2M) M140841*1 1 DB B
IC201 2114 5775 IC/LINEAR (POWER AMP) TA8248K 1 BI A
IC202 2114 1421 IC/PHOTO COUPLER PC900V 1 AK B

Q201,Q203 2250 1595 TRANSISTOR 2SB1240TV2R 2 AB B

Q205 2251 0672 TRANSISTOR 2SB1548-P.CS 1 AD B

Q202, Q204,

Q206-Q210

D201, D202 2390 3021 DIODE SRT14 2 AF B

D203, D205,

D207-D210

D206 2360 2044 DIODE/ZENER MTZJ6.2A-T77-T 1 AA C
D204 2360 1939 DIODE/ZENER MTZJ5.1C-T77-T 1 AA A

J201 3501 7049 JACK (POWER) HEC2305-01-330 1 AC A
J202 3612 0665 JACK (PHONE) YKB21-5006 1 AG B
J203 3612 0789 JACK YKB21-5010 1 AC B
J204 3501 4816 JACK/DIN YKF51-5051 1 AH B

N 3 6928 2130 PCB/ASSY (CN1M) M241172*1 1 BP C

LED301 2370 1414 LED MPR3338S-B149 1 AA B

N 4 6928 4500 PCB/ASSY (KY1M) M140687*5 1 BG B

D501 - D564 2301 0101 DIODE 1S2473T-77-T 64 AA B

N 5 6928 4510 PCB/ASSY (KY2M) M140688*5 1 BE B

D565 - D622 2301 0101 DIODE 1S2473T-77-T 58 AA B

6 6922 2720 KEY SET/LT WHITE M312118*1 4 AP A

7 6922 2730 KEY SET/LT WHITE M312118*2 1 AR A

8 6906 8481 KEY SET/LT BLACK 10P M140369A-3 2 AL A

9 6906 8591 KEY SET/LT BLACK 5P M140369A-4 1 AT A

N 10 5860 0679 SCREW 3X8 19 AA C

11 1909 2637 SCREW 3X18 21 AA C
12 6922 2762 RUBBER/CONTACT M211704B-1 4 AF A
13 6922 2772 RUBBER/CONTACT M211705B-1 1 AF A

2250 1592 TRANSISTOR 2SC1740STPR 7 AA B

2390 1344 DIODE 1SS133T-77-T 6 AA C

Console PCBs

Keyboard PCBs

Keyboard unit

- 21 -

N Item Code No. Part Name Specification Q PRICE CODE R

R : Rank

Panel unit

14 3831 1096 SPEAKER S12J89A 2 BH B
15 1908 6418 SCREW 4X8 13 AA C
16 3335 6804 LCD LD-B10427E 1 BO B
17 6927 3890 RUBBER/INTERCONNECTOR M440759-1 2 AV B
18 6927 3920 REFLECTOR M240922-1 1 AM C
19 3122 3698 CFL HMBV4BG2W106NLUAZG 1 AX C
20 6927 3420 HOLDER/CFL M440758-1 2 AA C

N 21 6927 3900 PACKING

22 6921 5031 KNOB M311859A-1 1 AA B
23 6927 0510 SWITCH/SLIDE KNOB CSB-08D 1 AD B
24 6927 3820 RUBBER/BUTTON M140821-1 1 AI B
25 6927 3830 RUBBER/BUTTON M240928-1 1 AD B
26 6927 3840 RUBBER/BUTTON M240929-1 1 AD B
27 6927 3850 RUBBER/BUTTON M140824-1 1 AG B
28 6927 3860 RUBBER/BUTTON M240931-1 1 AC B
29 6927 3870 RUBBER/BUTTON M240932-1 1 AK B
30 6903 2150 RUBBER/BUTTON M341091-1 1 AA B
31 6903 2150 SPRING/BATTERY(+) M41330-1 1 AA B
32 6902 6141 SPRING/BATTERY(-) M41226A-1 1 AB B

N 33 6928 4910 PLATE/DISPLAY M241161-1 1 AW C

34 5111 5163 SCREW 4X10 40 AA C
N 35 5860 0679 SCREW 3X8 18 AA C
N 36 5150 1640 SCREW 3X10 10 AA C
N 37 5161 3171 SCREW 4X12 8 AA C

38 6906 9218 COVER/BATTERY M311164H*17 1 AW B

Accessory

6906 9043 STAND/NOTE M340701*2 1 BK B

M440760-1

2 AC C

Notes: Q : Quantity

- 22 -

CASIO TECHNO CO.,LTD.

Overseas Service Division

Nishi-Shinjuku Kimuraya Bldg. 1F
5-25, Nishi-Shinjuku 7-Chome
Shinjuku-ku, Tokyo 160-0023, Japan