CTK-620L

,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,
100 RHYTHMS 100 SONG BANK
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,
RHYTHMS
SONG

,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,
TONE ,,,,,,,,,,,,,,,,,,,,,,,,,,,
BANK

,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,
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,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,
137 TONES

,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,, REVE
MUSICAL INFORMATION SYSTEM
SPOS
E/
TRAN /MIDI
SONG BANK
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,
RB REVERB
TUNE

,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,
HALL GM
TO (TIE) 3

,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,
RESPUCH STAGE LAYER
ONSE LAYER
7 8 9
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,
MODE VOLUME INTRO SYNCHRO/ENDING
METRONOME
ROOM
TOUCH
RESPONSE
SPLIT
MEMORY
SPLIT RHYTHM TONE
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,
TEMPO
KEY LIGHT STEP
4 5 6
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,
POWER
FULL RANGE
CHORD
MAX
BEAT
SONG BANK CONTROLLER
MEMORY
TRACK 1 TRACK 2 DEMO
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,
FINGERED
LEFT RIGHT
CASIO CHORD MP 1 2 3
,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,
NOMAL
ACCO ME KEY LIGHT STOP PLAY/PAUSE REW FF STEP 3-STEP LESSON
VOLU

,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,
STEP 1 STEP 2 STEP 3 REST
MIN
NORMAL/FILL-IN VARIATION/FILL-IN

,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,
START/STOP
1 2 3 0
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,

CTK-620L

ELECTRONIC KEYBOARD
 CONTENTS
Page
Specifications ............................................................................................................................................ 1
Block Diagram ........................................................................................................................................... 3
Circuit Description ..................................................................................................................................... 4
Adjustment .............................................................................................................................................. 12
Major Waveforms .................................................................................................................................... 13
Printed Circuit Boards ............................................................................................................................. 14
Schematic Diagrams ............................................................................................................................... 15
Exploded View ........................................................................................................................................ 28
Parts List ................................................................................................................................................. 29

SPECIFICATIONS

GENERAL
Keyboard: 61 standard-size keys, 5 octaves (with touch response on/off)
Key light system: Can be turned on and off (up to 10 keys can be lit at the same time)
Tones: 137 (128 General MIDI tones + 9 drum tones); with layer and split
Rhythm instrument tones: 61
Polyphony: 24 notes maximum (12 for certain tones)
Digital effects: 3 reverb types (HALL, STAGE, ROOM)
Auto accompaniment
Rhythm patterns: 100
Tempo: Variable (216 steps, = 40 to 255)
Chords: 3 fingering methods (CASIO CHORD, FINGERED, FULL RANGE
CHORD)
Rhythm controller: START/STOP, INTRO, NORMAL/NORMARL FILL-IN, VARIATION/
VARIATION FILL-IN, SYNCHRO/ENDING
Accomp volume: 0 to 127 (128 steps)
3-step lesson: 3 lessons (step 1, 2, 3)
Playback: Repeat play of a single tune
Song bank
Number of tunes: 100
Controllers: PLAY/PAUSE, STOP, FF, REW, LEFT, RIGHT
Musical information function: Tone, Auto Accompaniment, Song Bank numbers and names; staff nota-
tion, tempo, metronome, measure and beat number, step lesson display,
chord name, dynamic mark, fingering, pedal operation
Metronome: On/Off
Beat specification: 1 to 6
Memory
Songs: 2
Recording tracks: 2
Recording methods: Real-time, step
Memory capacity: Approximately 5,200 notes (total for two songs)
MIDI: 16 multi-timbre receive, GM Level 1 standard
Other functions
Transpose: 25 steps (–12 semitones to +12 semitones)
Tuning: 101 steps (A4 = approximately 440 Hz ± 50 cents)
Terminals
MIDI terminals: IN, OUT
Assignable jack: Standard jack (sustain, sostenuto, soft, rhythm start/stop)
Headphone/output terminal: Stereo standard jack
Output Impedance: 100 Ω
Output voltage: 4.5 V (RMS) MAX

—1—
Power jack 9 V DC
Power supply: 2-way
Batteries: Six D-size batteries
Battery life: Approximately 5 hours continuous operation on manganese batteries
AC adaptor: AD-5
Auto power off: Turns power off approximately six minutes after last key operation. En-
abled under battery power only, can be disabled manually.
Speaker output: 2.5 W + 2.5 W
Power consumption: 9 V --- 7.7 W
Dimensions (HWD): 96.1 × 39.1 × 14.4 cm (37 7/8 × 15 3/8 × 5 11/16 inches)
Weight: Approximately 6.0 kg (13.25 lbs) (without batteries)

ELECTRICAL
Current drain with 9 V DC:
No sound output 200 mA ± 20 %
Maximum volume 1090 mA ± 20 %
with 10 keys from F1 to A2 pressed in French Horn
Volume: maximum, Touch response: maximum
Reverb: stage
Speaker output level (Vrms with 4 Ω load each channel):
with key C1 for R-ch, F1 for L-ch in French Horn
Volume: maximun, Touch response: maximum 2300 mV ± 20 %
Reverb: stage
Phone output level (Vrms with 8 Ω load each channel):
with key C1 for R-ch, F1 for L-ch in French Horn
Volume: maximun, Touch response: maximum 180 mV ± 20 %
Reverb: stage
Output level (Vrms with 47 Ω load each channel):
with key C1 for R-ch, F1 for L-ch in French Horn
Volume: maximun, Touch response: maximum 2600 mV ± 20 %
Reverb: stage
Minimum operating voltage: 6.3 V

About General MIDI

General MIDI standardizes MIDI data for all sound source types, regardless of manufacturer. General MIDI
specifies such factors as tone numbering, drum sounds, and available MIDI channels for all sound sources.
This standard makes it possible for all MIDI equipment to reproduce the same nuances when playing
General MIDI data, regardless of the manufacturer of the sound source.
This keyboard supports General MIDI, so it can be used to play commercially available pre-recorded
General MIDI data and General MIDI data send to it from a personal computer.

—2—
 BLOCK DIAGRAM

SEG1 ~ SEG40
Working Storage LCD Driver
RAM (256K-bit) MIDI
LSI4 PO10, PO17
OUT IN LSI401 LCD
TC55257DFL-70L(EL) PO22, PO23

PA4 ~ PA6 SED1278F0A

COM1 ~ COM16
RACEB
Reset IC IC1
MA0 MD0
RN5VD40AA RESET FI0 ~ FI7
~ ~
SI0 ~ SI7 Illuminant
MA14 MD7

KC0 ~ KC7 Keyboard

Sound Source ROM MD0 ~ MD15 CPU
L21
(24M-bit) LED ~ L23
LSI3 LSI1 GA Driver
MD0 ~ 3
LH536PNV MA0 ~ MA19 LSI7 Q12 ~ Q14
MCSB0 GT913F(T) UPD65005 LED
MA0 ~ 2 GF-419 LED
Driver
RDCEB Q1 ~ Q11 L0
LCBE ~ L20
MCSB0, 1
Chip Selector KI0 ~ KI2
MA19
IC2,3
FI9
MA0, LRCK, SO FI10
MA1 BCK, SINK VDD
CE1B NMI Power Switch
ECEB
Effect RAM DSP
(256K-bit) EA0 ~ PA0, PA1
LSI5 EA14 LSI2 Buttons
TC55257DFL-
70L(EL) EIO0 ~ PB0 ~ PB3
HG51B277FB-1
EIO7
PB4
Assingnable Jack
LRCK
SO
BCK
LCDD LVDD DVDD VLCC
D/A Converter
VCC AVDD VDD VC
LSI6
UPD6379GR-E1

R OUT L OUT
APO Power Supply Circuit
Filter Q201 ~ Q208,
Phones/ Q213 ~ Q216 D206 ~ 208, D210
Output

Main
Speakers Volume

(L)
Power Amplifier
IC201
(R) TA8229K

—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) C6# (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)

BUTTON MATRIX
KC0 KC1 KC2 KC3 KC4 KC5 KC6 KC7
TEMPO TEMPO SYNCHRO/
KI0 MEMORY STEP 2 3 TONE 5 ENDING

KI1 STEP STEP 3 — 7 6 ACC. VOL. TIME METRO

KI2 STEP 1 0 + 4 DEMO TOUCH REVERB

LAYER TRACK 1/ PLAY/PAUSE STOP

FI9 RIGHT 2 RHYTHM 9 KEYLIGHT
TRACK 1/ FF REWIND TRANSPOSE/
FI10 SPLIT LEFT 1 SONG 8 TUNE/MIDI

PA0 PA1
FULL RANGE
PB0 INTRO CHORD
NORMAL
PB1 FINGERED
FILL-IN
VARIATION CASIO
PB2
FILL-IN CHORD
PB3 START/ NORMAL
STOP
—4—
LED MATRIX
L0 L1 L2 L3 L4 L5 L6 L7 L8 L9 L10

L21 A2# F4 B4 E5 A5 D6 G6 C7 A6# G6# F6#

L22 G2# E4 A4 D5 G5 C6 F6 B6 A5# C6# D6#

L23 C2 D4 G4 C5 F5 B5 E6 A6 G5# F5# D5#

L11 L12 L13 L14 L15 L16 L17 L18 L19 L20

L21 C3# D3# F3# G2 C3 F3 D4# C4# A3# G3#

L22 F2# D2# C2# F2 B2 E3 F4# G4# A4# C5#

L23 D2 E2 A2 D3 G3 A3 B3 C4

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

FI
Second contact (2) First contact (1)
KC
SI

NOMENCLATURE OF KEYS
C#2 D#2 F#2 G#2 A#2 C#3 D#3 F#3 G#3 A#3 C#4 D#4 F#4 G#4 A#4 C#5 D#5 F#5 G#5 A#5 C#6 D#6 F#6 G#6 A#6

C2 D2 E2 F2 G2 A2 B2 C3 D3 E3 F3 G3 A3 B3 C4 D4 E4 F4 G4 A4 B4 C5 D5 E5 F5 G5 A5 B5 C6 D6 E6 F6 G6 A6 B6 C7

—5—
POWER SUPPLY CIRCUIT

The power supply circuit generates seven 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

CPU, Reset IC, DSP, Sound source ROM, Working storage RAM, Effect RAM,
VDD +5 V
LED driver
DVDD +5 V CPU, Sustain jack, MIDI jack
AVDD +5 V DAC, Filter
LVDD +5 V GA
VCC +9 V Power amplifier
VLCC +2 V Pilot lamp
LCDD +5.6 V LCD driver

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. The CPU sends APO
signal to the power supply circuit, also sends a reset signal to the DSP.

Battery set VDD VDD

VDD
Reset signal
RESET PLE RESB DSP
RSTB LSI2
Reset IC CPU HG51B277FB-1
IC1 LSI1
RN5VD40AA GT913F
APO
POWER SCK0
NMI To power supply circuit
From power switch

—6—
CPU (LSI1: GT913F)

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 Not used
2 RXD0 In Not used
3 SCK0 Out APO (Auto Power Off) signal output
4 TXD1 Out MIDI signal output
5 RXD1 In MIDI signal input
6 SCK1 Out 1 MHZ synchronizing pulse output
7 AVCC In DVDD (+5 V) source
AC adaptor detection terminal.
+5 V when the keyboard is powered by batteries and
8 AN0 In
becomes 0 V to cancel the APO function when AC
adaptor is connected.
9 AN1 — Not used. Connected to ground.
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 MD0, MD1 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
FI0 ~ FI3
23 ~ 30 In Terminal for key input signal
SI0 ~ SI3
31 ~ 38 KC0 ~ KC7 Out Terminal for key scan signal
FI4 ~ FI7
39 ~ 46 In Terminal for key input signal
SI4 ~ SI7
47, 48 FI8, SI8 — Not used
49 FI9 In Terminal for button input signal
50 SI9 In Data bus for LCD driver
51 FI10 In Terminal for button input signal
52 SI10/P23 Out Data bus for the LCD driver
53 ~ 55 KI0 ~ KI2 In Terminal for button input signal
56 MWNB Out Write enable signal for the DSP

—7—
 Pin No. Terminal In/Out Function
57 ~ 76 MA0 ~ MA19 Out Address bus
Chip enable signal output for the sound source ROM,
77, 78 MCSB0, MCSB1 Out
working RAM and DSP
79 MCSB2 Out Not used
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

DIGITAL SIGNAL PROCESSOR (LSI2: HG51B227FB-1)

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 also controls button input/
output and GA.
The following table shows the pin functions of LSI2.

Pin No. Terminal In/Out Function

1 ~ 3, 80 PB0 ~ PB3 In Button input terminals
4 PB4 In ASSIGNABLE Jack input
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 20 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 GA
27 VSS3 In Ground (0 V) source
28 AD1 In Address bus
29 OEB Out Output enable signal for working storage RAM
30 WEB In Write enable signal for working strage RAM
31 VDD3 In +5 V source
32 CE2 In Chip enable signal input. High active.
33 AD0 In Address bus
—8—
 Pin No. Terminal In/Out Function
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 ~ 59, 61 EA0 ~ EA14 Out Address bus for the effect RAM
45 ECEB Out Chip enable signal output for the effect RAM
49 EOEB Out Output enable signal for the effect RAM
50 VSS3 In Ground (0 V) source
60 BWEB Out Write enable signal output for the effect RAM
62, 66, 70, 74, 78 VSS2 In Ground source
63, 67, 71, 75, 79 VDD2 In +5 V source
64, 65 PA0, PA1 Out Button scan signal output
68, 69, 77 PA2, PA3, PA7 — Not used
72 PA4 Out Data/command signal for LCD driver
73 PA5 Out Read/write signal for LCD driver
76 PA6 Out Chip enable signal for LCD driver

LCD DRIVER (LSI401: SED1278F0A)

The LCD driver can drive a dot matrix LCD having 40 segment and 15 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 LSI 401.

Pin No. Terminal In/Out Function

1 ~ 22, SEG1 ~ SEG40 Out Segment signal output
63 ~ 80
23 VSS — GND (0 V) source
Terminals for the built-in clock pulse generator.The external
24, 25 OSC1, OSC2 In/Out
resistor connected determines the oscillation requency.
LCD drive voltage input.
26 ~ 30 V1 ~ V5 In Those voltages are used for generating the stepped pulse of
the LCD drive signals.
31, 32 LP, XCLS — Not used
33 VDD In DVDD (+5 V) source
34, 35 FR, DO — Not used
36 RS In Data/command determination terminal.
High: data, Low: command
37 R/W In Read/write terminal. High: read, Low: write
Chip enable signal.
38 E In High: enable, the writing is done at fall edge.
Low: disenable
39 ~ 42 DB0 ~ DB3 — Not used. Connected to GND (0 V)
43 ~ 46 DB4 ~ DB7 In/Out Data bus
47 ~ 53, COM1 ~ COM7 Out Common signal/output
55 ~ 62 COM9 ~ COM16
54 COM8 — Not used

—9—
GATE ARRAY (LSI7: UPD65005GF-419)

The gate array can control 63 LEDs of key illuminators. In accordance with the command from the CPU, the
LSI is capable of controlling the illuminator LEDs. The following table shows the pin functions of LSI7.

Pin No. Terminal In/Out Function

3~6 MI0, MI1, MO0, MO1 — Not used
7, 26, 43, 58 GND In GND (0 V) source
8, 27, 44 VDD In LVDD (5 V) source
9 ~ 12 DB0 ~ DB3 In Data bus
13 ~ 15 MA0 ~ MA2 In Address bus
16 NCE In Chip enable signal
19 NWR In Write enable signal
20, 21 NRD, NRS — Not used
22 ~ 25, 28 ~ 32,
L0 ~ L20 Out LED drive signal output
35 ~ 42, 45 ~ 48
50 ~ 52 L21 ~ L23 Out LED common signal output
53 ~ 57, 59 L24 ~ L28, L29 — Not used
60 ~ 63 I0 ~ I3 — Not used
1, 2, 17, 18, 33,
NC — Not connected
34, 49, 64

DAC (LSI6: UPD6379GR)

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
SINC SCK1
L OUT Data Data
DSP CPU
SI SO LSI2 SI SO
DAC LSI1
Word clock HG51B277FB Word clock GT913F
LSI6
UPD6379GR LRCK WCKO WCKI LRCK
R OUT Bit clock Bit clock
CLK BCKI BCK

— 10 —
FILTER BLOCK

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

AVDD
AVDD

22 Ω

2SC1740SQ.R
10 V 22 µF
2SC1740SQ.R
+

50 V 0.22 µ

3.9K
22K
3.3K 4.7K 1K From DAC

1K
AG 12 µF
47 Ω

8.2 µF
+
50 V 3.3 µ

820PF
2.2K AG

6.3V 1000 µ
To main volume

10K
AG AG AG

AG

POWER AMPLIFIER (IC101: TA8248K)

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 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

— 11 —
 ADJUSTMENT

DISPLAY PCB
1) Items to be adjusted:

Item Measuring Instrument

Vop voltage setting Voltmeter

2) Adjustment and Test Point Locations

TP3 VR401
(TOP VIEW)

3) Equipment connection/Procedure

Vop voltage setting

Set Voltmeter

Output
TP3

Input Input Input Output Output

Adjust Adjust for
Connection Point Signal Connection Point
VR401 Voltmeter TP3 Adjust for 4.2 ~ 4.3 V reading
on voltmeter under the tem-
perature 20 ~ 25 °C.
Make fine adjustment accord-
ing to the next instruction.

Eye

Watching the LCD at a 37.6° angle to the horizontal, adjust Vop

37.6° voltage so that unenergized segments are seen dimly.

LCD

— 12 —
 MAJOR WAVEFORMS

1
5

4 6

1 Clock signal B1 3 MNI signal 5 LED common signal L23

Test point T5 JM connector pin 18 JN connector pin 1
2 Clock signal B2 4 APOFF signal 6 LED common signal L22
Test point T6 JS connector pin 12 JN connector pin 2
Key : C7

9 A

8 0

7 Key common signal KC0 9 CE signal for ROM A Sound signal (R)
JM connector pin 9 LSI3 LH536PNV pin 12 Test point T1
8 Key common signal KC1 0 CE signal for working RAM B Sound signal (L)
JM connector pin 8 LSI4 TC55257DFL pin 20 Test point T2

Tone : French horn, Volume : Maximum,

Touch speed : Maximum, Reverb : Stage
Key : A4

— 13 —
 PRINTED CIRCUIT BOARDS
Sub PCB JCM447-MA2M

2 1 12
Main PCB JCM447-MA1M

11
10
4
9

Top View Bottom View

3 7 8
— 14 —
 SCHEMATIC DIAGRAMS
Main PCB JCM447-MA1M

11 12 1

9
10

AT-49-30M
6 5

8 7

— 15 —
Sub PCB JCM447-MA2M

(5.6 V)

(0.7 V)

(5.6 V)

(5.6 V)
50V 1µ

(2 V)

— 16 —
Console PCB JCM447-CN1M

— 17 —
Console PCB JCM447-CN2M

— 18 —
Display PCB JCM447-LCD1M

— 19 —
Keyboard PCBs JCM618T-KY1M/KY2M

— 20 —
LED PCB JCM447-LD1M

— 21 —
LED PCB JCM447-LD2M

— 22 —
LED PCB JCM447-LD6

— 23 —
Console PCBs JCM447-CN3M/CN4M

— 24 —
Console PCB JCM447-CN5M

— 25 —
LED PCBs JCM447-LD4M/LD5M

— 26 —
LED PCB JCM447-LD3M

— 27 —
 EXPLODED VIEW
33

34

R-1

30
28
21
31

20 29
26
27
25
23
31 32 24 11
34 5

10

15

1 9 14
4

17
2
3
16

19

18

R-2

R-3
13 6
R-4

22
12
— 28 —
 PARTS LIST

CTK-620L

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 with-

out 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
IC1 2012 1883 IC/MOS RN5VD40AA-TR 1 B
IC2 2105 6427 IC/L-MOS TC7WH04FUTE12L 1 B
IC3 2105 4935 IC/C-MOS TC74VHV08F(TP1) 1 B
LSI1 2012 5005 LSI/MC GT913F(T) 1 A
LSI2 2012 4494 LSI HG51B277FB-1 1 A
LSI3 2012 5915 LSI LH536PNV 1 A
LSI4/LSI5 2012 5572 LSI/S-RAM T055257DFL-70L(EL) 2 A
LSI6 2105 4746 LSI/D-A CONVERTER UPD6379GR-E1 1 A
LSI7 2011 0812 LSI/GATE ARRAY UPD65005GF-419 1 A
Q1 - Q10 2259 2562 TRANSISTOR/DIGITAL UMS1NTL 10 A
Q11 2250 1169 TRANSISTOR 2SA1576AT106S 1 A
Q12 - Q14 2259 2737 TRANSISTOR 2SD2537T100VW 3 A
X1 2590 2700 OSCILLATOR/CRYSTAL AT-49-30M 1 B
X2 2590 2699 OSCILLATOR/CERAMIC EF0B2005E0 1 B
1 6926 3820 M447-MA1M PCB ASSY2 M240791*2 1 A
Sub PCBs
D201/D202 2390 3021 DIODE/SHOTTKY SRT14 2 B
D206 2360 3056 DIODE/ZENER HZS6A2LTD-T 1 A
D207/D210 2360 1085 DIODE/ZENER HZS6B1LTD-T 2 A
D208 2360 1946 DIODE/ZENER MTZJT-775.6C 1 A
IC201 2114 5784 IC/LINEAR TA8229K 1 B
IC202 2114 1421 IC/PHOTO COUPLER PC900V 1 B
IC203 2114 1799 IC/LINEAR M5218APR 1 B
J201 3501 7049 JACK/DC HEC2305-01-330 1 A
J202 3612 0665 JACK/PHONE YKB21-5006 1 A
J203 3612 0789 JACK YKB21-5010 1 A
J204 3501 4816 JACK/DIN YKF51-5051 1 B
Q201 2250 1591 TRANSISTOR 2SB12371V2R 1 A
Q202,Q204
Q207 - Q209 2250 1592 TRANSISTOR 2SC1740STPR 9 A
Q213 - Q216
Q203 2250 1594 TRANSISTOR 2SA1585STPR 1 A
Q205 2250 1593 TRANSISTOR 2SD1858TV2R 1 A
Q206 2251 0672 TRANSISTOR 2SB1548-P.CS 1 A
2 6926 3000 M447-MA2M PCB ASSY M140693*1 1 A
Console PCBs
LED301 2370 0343 LED LN28RPX-(TT) 1 B
VR301 2765 2178 POTENTIOMETER EWASC2C95B23 1 A
3 6926 3060 M447-CN5M PCB ASSY M240780*1 1 A
4 6926 3020 M447-CN1,2,3,4M PCB ASSY M140690*1 1 A
Display PCBs
LSI401 2012 5569 LSI/LCD DRIVER SED1278F0A 1 A
T401 2590 2177 THERMISTOR TBPS1R103J440H5Q 1 B
VR401 2775 3286 POTENTIOMETER EVM3SSX50B53 1 A
5 6926 3050 M447-LCD1M PCB ASSY2 M240784*1 1 A
Keyboard PCBs
LED451 - LED475 2370 1395 LED SLR-33JTTD7 25 B
LED501 - LED536 2370 1394 LED SLR-33JTTJ2 36 B
6 6926 3090 M618T-KY1M PCB ASSY M140687*1 1 B
7 6926 3100 M618T-KY2M PCB ASSY M140688*1 1 B
8 6926 3110 M447-LD6 PCB ASSY M240779*1 1 B
9 6926 3130 M446-LD3M PCB ASSY M240428*2 1 B
10 6926 3140 M446-LD4M PCB ASSY M240429*2 1 B
Notes: Q – Quantity per unit
R – Rank

— 29 —
Item Code No. Part Name Specification Q R

11 6926 3150 M446-LD5M PCB ASSY M240430*2 1 B

12 6926 3160 M447-LD1M PCB ASSY M240777*1 1 B
13 6926 3170 M447-LD2M PCB ASSY M240778*1 1 B
Keyboard unit
14 6925 1700 KEY SET/WHITE/LSK-CB M340489*1 4 A
15 6925 1710 KEY SET/WHITE/LSK-CS M340489*2 1 A
16 6925 1720 KEY SET/BLACK LSK10P M140369-1 2 A
17 6925 1730 KEY SET/BLACK LSK5P M140369-2 1 A
18 6922 2760 RUBBER/CONTACT LT-CB M211704-1 4 A
19 6922 2770 RUBBER/CONTACT LT-CS M211705-1 1 A
Panel unit
20 3335 6616 LCD LD-B10175A-1 1 A
21 6926 5570 CONNECTOR/FOR LCD M440488-2 2 A
22 6918 1630 COVER/BATTERY M311164*1 1 B
23 6921 5030 KNOB/SLIDE M311859-1 2 B
24 6926 3880 BUTTON/RUBBER 447A M140632-1 1 B
25 6926 3890 BUTTON/RUBBER 447B M240693-1 1 B
26 6926 3900 BUTTON/RUBBER 447C M240694-1 1 B
27 6926 3910 BUTTON/RUBBER 447D M240695-1 1 B
28 6926 3920 BUTTON/RUBBER 447E M240696-1 1 B
29 6926 3930 BUTTON/RUBBER 447F M240697-1 1 B
30 6926 3940 BUTTON/RUBBER 447G M240698-1 1 B
31 6926 3950 BUTTON/RUBBER 447H M340681-1 2 B
32 6909 5890 CONTACT/SLIDE CSB-12D 1 A
33 6926 5580 PLATE/DISPLAY M340682-2 1 C
34 3831 0833 SPEAKER S12J49A 2 B
Accessory
6926 4630 STAND/MUSIC M340769*1 1 B

Notes: Q – Quantity per unit

R – Rank

— 30 —
 CASIO TECHNO CO.,LTD.
8-11-10, Nishi-Shinjuku
Shinjuku-ku, Tokyo 160, Japan
Nov. 1997
Telephone: 03-3347-4926
MA1100571A Printed in Japan