CASIO AT1 Service Manual

AT-1

INDEX

(without price)

ELECTRIONIC KEYBOARD

CONTENTS

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

Replacing the DSP (HG51B155FD) . . . . . . . . . . . . . . . . . . . . . . . . 2

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

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

Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Major Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

PCB View and Major Check Points . . . . . . . . . . . . . . . . . . . . . . . 14

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

Exploded View. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

IC Lead Identification and Internal Diagram . . . . . . . . . . . . . . . . 19

Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

SPECIFICATIONS

General

Number of Keys: 61
Polyphonic: 32-note
Preset Tones: 100

Tone Expander: Layer, Split

Keyboard Controls: Touch Response: On/Off

Touch Sensitivity: Light/Middle/Heavy
Key Transpose: Range from F# to F by a semitone increment
Oriental Scale Control: Tune: On/Off, Mode: Cent/

Tuning Rang: Quarter tone (±99 cents) and
Scale Memories: 4
Auto-Rhythms: 50

Tempo Control: 40 to 255
Auto-Accompaniment: CASIO Chord/Fingered/Full-Range Chord

Controller: Variation, Fill-In, Intro/Ending
Magical Presets: 50; BREAK BEAT 20

FREE SESSION 24
KEY SPLIT 6

Digital Effects: 10; Reverb-1, Reverb-2, Reverb-3, Chorus, Tremolo, Phase Shifter,

Organ SP, Enhancer, Flanger, EQ Loudness
Sound/Control Pads: 4
Pad Variations: 32; Phrases: 10, Drums: 10, Percussion: 10, Controllers: 2
Song Memory: 1; System: Real-time recording

Memory Capacity: Approx. 700 notes
Pitch Bender: Bend Range; 2 semitones/3 semitones
Registration Memories: 6
Registration Items: Tone Number, Rhythm Number, Tempo, Accompaniment Mode,

Accompaniment Volume, Effects, Layer On/Off, Split On/Off,
Chord On/Off, Accompaniment Scale On/Off, Pad Variation,
Assignable Jack, Auto-Accompaniment Controller, MIDI (Channel On/Off,

GM On/Off, Local Control On/Off, Bend Range)
Tuning Control: 440Hz ± 50 cents
Terminals: Headphone Jack [Output Impedance: 150 Ω, Output Voltage: 5.2 V(rms)

MAX], Assignable Jack, MIDI Jacks (IN, OUT), AC Adaptor Jack (9 V)
Built-In Speakers: 12 cm dia. 2.5 W Input Rating: 2 pcs.
Power Source: 2-way AC or DC source

AC: AC adaptor AD-5

DC: 6 D size dry batteries

Battery life: Approx. 5 hours by manganese batteries R20P(SUM-1)
Auto Power Off: Approximately 6 minutes after the last operation
Power Consumption: 7.7 W
Dimensions (HWD): 129 x 942 x 367 mm

5-1/16 x 37-1/16 x 14-7/16 inches
Weight: 5.3 kg (11.7 lbs) excluding batteries
Standard Accessory: Music stand, Dust cover

Koma

koma

(±5

komas

)

— 1 —

Electrical

Current Drain with 9 V DC:
No Sound Output 260 mA ± 20%
Maximum Volume 930 mA ± 20%

with key C3 pressed in Synth-Bass tone and effect No. E-9
Split: On, Layer: On, Oriental scale: On/Cent
Song memory: Play, Volume; maximum, Touch: maximum

Line Output Level (Vrms with 47 KΩ load each cannel):

with key F2 pressed in FSynth-Bass tone 2480 mV ± 20%

Phone Output Level (Vrms with 8 Ω load each channel):

with key C3 pressed in FSynth-Bass tone 97 mV ± 20%

Speaker Input Level:

with key C3 pressed in FSynth-Bass tone 2240 mV ± 20%

Minimum Operating Voltage: 6.3 V

REPLACING THE DSP (HG51B155FD)

Note: To increase productivity ,the DSP HG51B155FD is sticked on the main PCB with a double-side
adhesive tape, then its leads are soldered.

Remove the DSP according to the following procedures.

1. Prepare isopropyl alcohol and a flat IC desoldering machine (Spot Heater HS-600).

2. Apply plenty of the alcohol to the adhesive tape from the reverse side of the main PCB. (Fig.1)
There is a hole on the PCB just under the LSI, and the adhesive tape can be seen through the hole.

3. Leave it more than one minute so that the alcohol weaken adhesive power fully.

4. Using a proper size of nozzle, apply heat to leads of the LSI with the desoldering machine.

5. Grasp the LSI with tweezers, and using gentle force vibrate the tweezers to feel melting solder. (Fig.2)

6. Remove the LSI after meltingsolder at every leads wholly.

Spot Heater HS-600

Alcohl

HG51A115A

LSI-S

— 2 —

Fig.2Fig.1

BLOCK DIAGRAM

Keyboard

FI0 ~ FI7

SI0 ~ SI7

Key Touch LSI

LSI106

HG52E35P

KC0 ~
KC7

A0 ~ A2

Reset IC

IC104

RE5VA35AA

Working Strage

RAM (64K-bit)

LSI104

SRM2264LC90,10

A0 ~
A12

D0~D7

A0 ~ A14

Q109 ~ Q116

A0 ~ A3

La ~ Lg, Lp

LED driver

LD0 ~ LD7

RESET

CPU

LSI102

HD6433298A36P

7-Seg.

LED

LEDs

CLK

KO

LC1 ~ LC4

LO0 ~ LO4

KO Signal
Generator
IC303/304

TC74HC174P

KI1 ~ KI7

POWER

Power Switch

LED driver
IC301/302
BA612

KO0 ~ KO10

Buttons

VDD

MIDI

OUT

IN

Effect RAM

(64K-bit)

LSI107

SRM2264LC90,10

Speakers

EA0 ~ EA12

ED0 ~ ED7

Output

DSP

LSI105

HG51B155FD

WCK1 SLOP BCK

D/A Converter

LSI101

UPD6376CX

Filter

IC105

Main
Volume

Power Amplifier

IC102

LA4598

Filter

IC105

RA0 ~ RA19

RD0 ~ RD15

VC

Sound Source ROM

(16M-bit)

LSI103

TC5316200CP-C106

APO

LVDD

VCC

Power Supply Circuit

AVDD

IC101, Q1 ~ Q4

DVDD

VDD

— 3 —

CIRCUIT DESCRIPTION

Key Matrix

KC0 KC1 KC2 KC3 KC4 KC5 KC6 KC7
FI0 C2 1 C#2 1 D2 1 D#21 E2 1 F2 1 F#21 G2 1
SI0 C2 2 C#22 D2 2 D#22 E2 2 F2 2 F#2 2 G2 2
FI1 G#21 A2 1 A#2 1 B2 1 C3 1 C#3 1 D3 1 D#3 1
SI1 G#22 A2 2 A#2 2 B2 2 C3 2 C#32 D3 2 D#32
FI2 E3 1 F3 1 F#3 1 G3 1 G#31 A3 1 A#3 1 B3 1
SI2 E3 2 F3 2 F#3 2 G3 2 G#32 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 C4 1 C#4 1 D4 1 D#4 1 E4 1 F4 1 F#4 1 G4 1
SI4 C4 2 C#4 2 D4 2 D#4 2 E4 2 F4 2 F#4 2 G4 2
FI5 E5 1 F5 1 F#5 1 G5 1 G#51 A5 1 A#5 1 B5 1
SI5 E5 2 F5 2 F#5 2 G5 2 G#52 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#61 A6 1 A#6 1 B6 1 C7 1
SI7 G#62 A6 2 A#6 2 B6 2 C7 2

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

Key

FI

Second contact 2

First contact 1

KC

SI

Nomenclature of Keys

C#2

F#2D#2

C#3A#2G#2

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

G#6F#6D#6

A#6

C2 D2E2F2

G2

A2 B2 C3 D3

E3

F3 G3 A3 B3 C4 D4 E4 F4 G4 A4 B4 C5 D5 E5 F5 G5 A5 B5

— 4 —

C6

B6A6G6F6E6D6

C7

Button Matrix

KI1 KI2 KI3 KI4 KI5 KI6 KI7

KO0 Registration 3 2 1 0

KO1 Control Demo Layer Split

KO2 Tone Rhythm 9 8 7 +

KO3 Accomp 6 5 4 -

Transpose/

Tune

Magical

Preset

Digital

Effect

Memory

Touch

Response

KO4 G# down A down A# down B down G down

KO5 ScaleMode ScaleTune B up A# up A up G# up G up

Song

KO6 Intro Start/Stop

Tempo

Down

Tempo

Up

Synchro/

Ending

Variation/

Fill-In

Normal/

Fill-In

KO7 C up C# up D up D# up E up F up F# up

KO8 C down C# down D down D# down E down F down F# down

KO9 Mode Pad B Pad D Pad A Pad C

KO10 Rec

Scale

Memory 1

Scale

Memory 2

Scale

Memory 3

Scale

Memory 4

Reset Circuit

Initial reset
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 strage RAM.
Power ON reset
When the power switch is pressed, the CPU receives a low pulse of POWER signal. The CPU provides
APO signal to the power supply circuit, then provides RESET signal to the DSP, the key touch LSI and
the KO signal generators.

VDD

From power switch

Battery set

Reset IC

IC104

RE5VA35AA

RESET

POWER

VDD

CPU

LSI102

HD6433298A36P

-NMI

-RESET

DVDD

KO Signal Generator

IC303/304

TC74HC174P

Working Strage RAM

LSI104

SRM2264LC90,10

HG51B155FD

VDD

Key Touch LSI

LSI106

HG52E35

DVDD

DSP

LSI105

DVDD

— 5 —

CPU (HD6433298A36P)

The 16-bit CPU contains a 32k-bit ROM, a 1k-bit RAM, seven 8-bit I/O ports, an A/D convertor and serial
interfaces. The CPU accesses to the working strage RAM, the DSP and the key touch LSI. The CPU also
controls buttons, bender input, LEDs and MIDI input/output.
The following table shows the pin functions of the CPU.

Pin No. Terminal In/Out Function

1 P40 Out KO signal data output
2 P41 Out Clock for KO signal data
3 P42 Out APO (Auto Power Off) signal output. ON: High OFF: Low
4 P43 Out Read enable signal output
5 P44 Out Write enable signal output
6 P45 Not used
7 P46 Out 10 MHz clock output
8 P47 In Wait signal input. Connected to +5 V.

9 TXD Out MIDI signal output
10 RXD In MIDI signal input
11 P52 Out Reset signal output
12 -RESET In Reset signal input
13 -NMI In Power ON signal input
14 VCC In +5 V source
15 -STBY In Standby signal input. Connected to +5 V.
16 VSS In Ground (0 V) source

17, 18 XTAL,EXTAL In 20 MHz clock input
19, 20 MD1, MD0 In Mode selection input.(Internal ROM mode --- MD1: High MD0: Low)

21 AVSS In Ground (0 V) source for the built-in DAC
22 AN0 In Analog input. Connected to ground.

23 ~ 29 P71 ~ P77 In Ternimal for button input signal

30 AVCC In +5 V source for the built-in DAC

31 ~ 38 P60 ~ P67 Out LED segment signal output

39 VCC In +5 V source
40 P27 Not used

41 ~ 56 P26 ~ P10 Out Address bus

48 VSS In Ground (0 V) source

57 ~ 64 P30 ~ P37 In/Out Data bus

Digital Signal Processor (HG51B155FD)

Upon receipt of note numbers and their velocities, the DSP reads sound and velocity data from the sound
source ROM in accordance with the selected tone; the DSP can read rhythm data simultaneously when a
rhythm pattern is selected. Then it provides 16-bit serial signals containing data of the melody, chord,
bass, and percussion to the DAC. The DSP also adds the selected effect to the sound data using a 64k-bit
RAM.
The following table shows the pin functions of the DSP.

— 6 —

Pin No. Terminal In/Out Function

1 ~ 8 CD0 ~ CD7 In/Out Data bus
9, 10 Not used

11 GND7 In Ground (0 V) source
12 CK16 Out 16.384 MHz clock output
13 VCC6 In +5 V source
14 CK0 In Clock input. Connected to terminal CK16.
15 TCKB Not used
16 VCC1 In +5 V source
17 GND1 In Ground (0 V) source

18, 19 XT0, XT1 In/Out 16.384 MHz clock input/output. Connected to a crystal oscillator.

20 SGL In System control terminal. Single chip system: Open
21 CCSB In Chip select signal input

22 ~ 25 CA0 ~ CA3 In Address bus

26 CE0 In Not used. Connected to ground.
27 CWRB In Write enable signal
28 CRDB In Read enable signal

29 ~ 32 Not used

33 RESB In Reset signal input
34 TESB In Not used. Connected to +5 V.

35 ~ 39 Not used
40 ~ 49

52 ~ 57

RD0 ~ RD15 In Address bus for the sound source ROM

50 VCC2 +5 V source
51 GND2 Ground (0 V) source
58 RA23 Out Not used
59 RA22 Out Chip select signal for the sound source ROM

60, 61 RA20, RA21 Out Not used

62 ~ 73
75 ~ 82

RA0 ~ RA19 Out Address bus for the sound source ROM

74 GND5 In Ground (0 V) source
83 WOK2 Out Word clock output. Not used.
84 VCC3 In +5 V source
85 GND3 In Ground (0 V) source
86 WOK1 Out Word clock for the DAC
87 SOLM Out Serial data output. Not used.
88 SOLP Out Serial sound data output for the DAC
89 BOK Out Bit clock output for the DAC

90 ~ 92 Not used

93 VCC5 In +5 V source
94 EA14 Out Not used

95, 97

99 ~ 105
107, 109

EA0 ~ EA12 Out Address bus for the effect RAM

110, 112

— 7 —

DAC (UPD6376CX)

UPD6376CX is a two-channel 16-bit Digital to Analog Convertor consisting of resistor string, output
amplifier and zero offset circuit.

Pin No. Terminal In/Out Function

1 SEL In Mode selection terminal. Connected to ground.
2 D.GND In Ground (0 V) source for internal digital circuit
3 NC Not used
4 DVDD In +5 V source for internal digital circuit
5 A.GND In Ground (0 V) source for internal analog circuit
6 R.OUT Out Right channel sound waveform output
7 A.VDD In +5 V source for internal analog circuit
8 A.VDD In +5 V source for internal analog circuit

9 R.REF In Reference voltage terminal. Connected to a capacitor.
10 L.REF In Reference voltage terminal. Connected to a capacitor.
11 L.OUT Out Left channel sound waveform output
12 A.GND In Ground (0 V) source for internal analog circuit
13 LRCK In Word clock (L/R separation signal) input.
14 LRSEL In Not used. Connected to ground.
15 SI In Sound data input
16 CLK In Bit clock input

Key Touch LSI (HG52E35P)

By counting the time between first-key input signal FI and second-key SI from the keyboard unit, the key
touch LSI detects key velocity of 256-step. Then the LSI sends the CPU the note number and its velocity
data.

Key touch LSI

RD

APO

WR

CLOCK

A12
A14

RESET

Data bus

Address bus

LSI106

HG52E35P

CRDB
CWRB
CKI
CCSB

RESB
CD0
CD7
CA0 ~ CA2

SI0

SI7

KC0

Key scan signal

~

KC7

FI0

Key input signal

FI7

Keyboard

KC

First contact

FI

SI

Second contact

— 8 —

Pin No. Terminal In/Out Function

96 EWEB Out Write enable signal output for the effect RAM

98 EA13 Out Not used
106 EOEB Out Read enable signal output for the effect RAM
108 VCC7 In +5 V source
111 ECEB Out Chip select signal output for the effect RAM

113 ~ 117 Not used

118 VCC4 In +5 V source
119 GND4 In Ground (0 V) source

120 ~ 122 Not sued
123 ~ 130 ED0 ~ ED7 In/Out Data bus for the effect RAM

131 GND5 In Ground (0 V) source

132 ~ 134 Not used. Connected to ground.

135, 136 Not used

Block diagram of DSP and DAC circuit

Sound Source ROM

LSI103

TC5316200CP-C106

CE

A0 ~ A19 D0 ~ D15

RA22

RA0 ~
RA19

RD0 ~
RD15

SOLP: Sound data
BOK: Bit clock
WOK1: Word clock

A13

A14

RD
APO
WR

RESET

D0 ~ D7
A0 ~ A3

CCSB

CRDB

CWRB

ECEB EOEB

OE

CS

DSP

LSI105

HG51B155FD

EWEB

WE

ED0 ~
ED15

D0 ~ D15

EA0 ~
EA12

A0 ~ A12

Effect RAM (64K-bit)

LSI107

SRM2264LC90,10

SOLP

BOK
WOK1

DAC
LSI101

SI

CLK

LRCK

UPD6376CX

PG

X102

16.384MHz

ROUT

LOUT

— 9 —

The following table shows the pin functions of the key touch LSI.

Pin No. Terminal In/Out Function

1 REQB Out Interrupt request. Not used.

FI8 ~ FI10

In Key input signal. Connected to + 5 V.2, 3, 60 ~ 63

SI8 ~ SI10

4 VCC In +5 V source
5 CRDB In Read enable signal
6 CWRB In Write enable signal
7 CCBB In Chip select signal

8, 9, 11 T, STBY, W In Not used. Connected to +5 V.

10 RESB In Reset signal
12 CKI In 10 MHz clock input

13, 14 TMD, TST In Not used. Connected to ground.

15 CKO Out Not used
16 GND In Ground (0 V) source
17 XIN In Not used. Connected to ground.
18 XOUT Out Not used
19 TRES In Not used. Connected to ground.

20 ~ 23, 25 ~ 28 CD0 ~ CD7 In/Out Data bus

24 GND In Ground (0 V) source

29 ~ 31 CR0 ~ CR2 In Address bus

32 VCC In +5 V source

33 ~ 39, 41 ~ 43 FI0 ~ FI7,

In Key input signal

53 ~ 55, 57 ~ 59 SI0 ~ SI7

40 VCC In +5 V source

44 ~ 47, 49 ~ 52 KC0 ~ KC7 Out Key scan signal

48, 56 GND In Ground (0 V) source

64 VCC In +5 V source

Filter Block

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

10V22µ

To main volume

IC105
M5218APR

-

+

C333(H)

1K

C222(H)

AG

— 10 —

Q107/108
2SC1740

1K 1K

C103(H)

AG

AVDD

1K

AG

AVEE

18K

50V1µ

From the DAC

Power Amplifier (LA4598)

The power amplifier is a two-channel amplifier with standby switch. The following figure shows the inter­nal diagram of the amplifier.

Internal Diagram of LA4598

2

Ch2 B.S.

Ch1 IN

Ch1 N.F.

Pre GND

6

5

8

Input
Amp.

Pre-drive
Amp.

Power
Amp.

TSD protector

3

Ch1 OUT

1

Power GND

VCC

4

D.C.

Ch2 IN

Ch2 N.F.

7

10

11

Bias circuit

Input
Amp.

Pre-drive
Amp.

Stand by

Power
Amp.

9

Standby

Ch2 OUT

12
13

Ch2 B.S.

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 output from the CPU.

Name Voltage For operation of

VDD +5 V CPU, Reset IC, Working strage RAM
DVDD +5 V DSP, Key controller, Sound source ROM, Effect RAM, DAC, KO siginal generator
AVDD +5 V DAC Filter
LVDD +4.5 V LED Driver

VCC +9 V Pilot lamp

VC +9 V Power amplifier

— 11 —

Bender

Volume

WIRING DIAGRAM

JCM719-CN2M

JG1

JG2

JG3

JG4

JG5

JG6

Lp

LC3

JG3

JC10

JC11

LC4

JG4

JG5

JC12

LgLfLe

JG6

JC1

JC2

JC3

JC4

JC5

LC1

LC2

JG1

JG2

JCM719-CN1M

JC6

JC7

JC8

JC9

JG7

JG7

JG8

JG9

LdLcLb

JG8

JD1

JG9

JG10

JG10

JD2

JG11

JG11

JD3

JG12

La

JG12

JD4

JD5

JD6

JD7

JD8

JD9

JD10

JD11

JD12

BATT+
BATT-

DG

DVDD

BENDER

JF3

JF2

JF1

JE5
JE4
JE3
JE2
JE1

AG
L OUT
R OUT

R IN

L IN

DC JACK
PHONE/OUTPUT
ASSIGNABLE JACK
MIDI IN
MIDI OUT

JA1

JA2

JA3

JA4

JA5

JA6

JE5
JE4
JE3
JE2
JE1

JA7

LG

PWLD

JC1

JC2

JCM719-MA2M

JA8

JA9

JA10

JA11

KI1

KI2

KI3

KI4

JC5

JC6

KI5

JC7

POWER

JC3

JC4

Main Volume

JA12

JA13

JA14

JA15

JA16

Lc

JD1

JC8

KI6

JC9

KI7

JC10

La

JC11

Lb

JC12

JCM719-MA1M

JB1

JB2

JB3

JB4

Ld

LeLfLg

JD2

JD3

JB5

JB6

JD4

JB7

JD5

JB8

Lp

JD6

JB9

CLK

JD7

JB10

KO9

JD8

JB11

KO

JD9

JB12

DVDD

RESET

JD10

JD11

JB13

JB14

DG

JD12

JB15

JB16

BATTERY

COMPARTMENT

FI1

JA1

FI2

FI0

SI0

SI1

JA2

JA3

JA4

JA5

M617T-KY1M

SI2

JA6

SI3

JA7

FI3

JA8

KC0

JA9

KC1

JA10

KC2

JA11

KC3

JA12

KC4

KC5

JA13

JA14

— 12 —

KC6

JA15

KC7

JA16

KC0

JB1

KC1

KC2

KC3

KC4

JB2

JB3

JB4

JB5

M617T-KY2M

KC5

JB6

FI4

JB7

SI4

JB8

KC6

JB9

KC7

JB10

SI5

JB11

SI6

JB12

JB13

SI7

FI5

JB14

FI6

JB15

FI7

JB16

MAJOR WAVEFORMS

F

F Button scan signal KO0

IC304: TC74HC174AP pin 2

G Button scan signal KO1

IC304: TC74HC174AP pin 5

G

H

I

H Button scan signal KO2

IC304: TC74HC174AP pin 7

I Button scan signal KO3

IC304: TC74HC174AP pin 15

J DAC output

UPD6376CX pin 11

K DAC output

UPD6376CX pin 6

J

K

Tone: No. 78
Key: A4
Touch response: OFF
Digital effect: OFF
Volume: Maximum

1

2

1 Main clock pulse

HD6433298A36P pin 7

2 DSP clock pulse

HG51B155FD pin 12

Power switch ON

3

4

5

3 POWER signal

HD6433298A36P pin 13

4 APO signal

HD6433298A36P pin 3

5 RESET signal

HD6433298A36P pin 11

B

C

D

E

B Bit clock BOK

UPD6376CX pin 16

C L/R clock WOK1

UPD6376CX pin 13

D Sound data SOLP (Note OFF)
E Sound data SOLP (Note ON)

UPD6376CX pin 15

6

7

6 LED segment signal LD0

7 LED segment signal LD3

HD6433298A36P pin 31

HD6433298A36P pin 34
Display: "0.0"

8

9

0

A

8 Key scan signal KC0

HG52E35P pin 44

9 Key scan signal KC1

HG52E35P pin 45

0 Key scan signal KC2

HG52E35P pin 46

A Key scan signal KC3

HG52E35P pin 47

L

M

L Power amp. input

LA4598 pin 10

M Power amp. input

LA4598 pin 6

— 13 —

D104

PS

JF

W
O

L104

3
2

EF101

1

1

15

JE

W
0

321

EF102

NO.

175

JE

5

5

75

L103
FB111

GR

C105

Q102

R104
R105

C121

J101

L121

5

125

75

C101
Q101

E

JF

5

75

B

D111

R103

R102

E

VCC

E

Q104

D112

5

D105

C120

R127

R132

1

1

JE

JE
5

5

3

312

VR101

D103

R111

C113

E

C103

C112

E

150

E

Q103

B

R291
R110
AVDD

DVDD R106

D101

75

VC

100

150

R114

R113

C116R117

R292

C111

C110

300

250

GR

3
3

MAIN VOL

Q105

L101

L102

C212

FB102

J102

L106

C115

C114

R112

R116

R115

100

C108

C127

300

300

175
175

150

Q122

BE

Q121

BE

R294

C211

5

R108

D107

E

BK

BK R

FB103

R118

100

5

R293

C104

PZ

C117

C107

IC102

5

IC101

C140

B

C182

L107

D109

R134

R

J103

100

C123

31

C145

5

C138

R295

R147

D102

150

C139

R148

C213

C171

FB104

C124

R120

C125

5

C126

R121

R126

C119

R125

C118

R124
R123

C131

R129

C130

R128
R131
R130

C128

C155

C143

C164

C102

R149

VDD

C146

IC104

R138

31

C132

C159

R173

R166

5

R184
R183
R182
R181

R155

R135

LSI101

C160

75

R174

R177

R156

C135

R136

C168

R176

100

C166

Q109

R157

12

202123 23

FB107

C137

C171

C161

75

C176

C196

175

B

E

R158

121

100

R190

R140

R143

C170

R199
R198
R197

4

3

6

E

Q110

R141

R139

75

150

R185

75

1
5

7

B

R191

R142

175

IC107

Q111

1

J104

C136

225

175

B

E

R200

Q112

MC102

1

C214

125

5

C185

R195
R194
R193
R192

LSI102

Q113

B

E

R201

75

R211R213

175

R212

LSI103

R214

150

300

200

200

C175

Q114

Q115

B

EB

E

R202

R203

C150

JD 12

LSI104

Q116

EB

R205

R204

EF103

JD

C149

C148

12

PCB VIEW AND MAJOR CHECK POINTS

R133

R162

R167

C153
R168

R163

X101

C156

D106

C165

C167

R150

C152

FB109

R178
R179
R180

75

R151

175

FB106

IC103

C162

R172
R171

75

FB110

MC101

R152

R153

JC

R159

R161

100

R175

R154

R165

125
125

5

100

5

R144

C129

IC105

100

125

R137

Q106

1

L108

C122

R160

Q108

C154
C174

R169

D108

C134

FB105

C133

Q107

BBEE

R164

R146

R145

C144

R170

C157

200

B

C141
C142

E

C147

JC

C173

C172

C163

75

C179

75

250

5

225

275

250

C180

C181

LVDD

75

EB

13 12

R186

R187

100

R188

125

C178

175

125

C197

100

IC106

5

C177

275

200

250

175

R206

C194

R245

R243

R268

R267

14 15

L110

C199

L111

100

100

C196

C186

R235

R269

1

100
100
100
100

R242

R270

C188

200

225

C195

LSI105

150

150

150

C191

C190

C189

125

100

C184

R210

225

C193

R216

FB114

FB113

R217

X102

175

150

5
5
5
5
5
5

100

100

R209

R208

FB112

300

75
75

R215

R220
R221
R222
R223
R224
R225
R226
R227
R228
R229
R230

C192

R219

75

R207

100

LSI106

R218

C187

250

150

R231
R232
R233
R234

R236

125225

R244

R271

125

1JA16

JA

16

R274

LSI107

150

R250

R237

R238

R241

275

R246

R247

R272

R273

C200

R249

C198

R240

R248

R275

5

R264
R265

R251
R252
R253
R254
R255
R256
R257
R258
R259
R260

R262
R263
R266

R239

R283
R282
R281
R280
R279
R278
R277
R276

75

R261

W

W

PR
BL

BL

2

1

JB

1

JB

5

17

17

— 14 —

PCB JCM719-MA1M

SCHEMATIC DIAGRAMS

21

20

12

13

22

23

14 15

1

4

2

3

5

8 9 10 11

6 7

— 15 —

PCBs JCM719-CN1M, CN2M, MA2M

19

16 17

18

— 16 —

PCBs JCM617T-KY1M, KY2M

— 17 —

EXPLODED VIEW

7

10

8

10

S-1

9

16

S-1

15 17

14

21

11

12

13

18

17

19

S-3

3-1

20

3

22

S-2

3-1

2

2-1

— 18 —

26

S-2

25

27

S-1

4

23

24

24

S-2

1

28-3

S-1

28-2

28-5

28

28-4

S-5

30

28-1

6

29

6-1

S-4

5-1

5

32

S-4

31

S-5

IC LEAD IDENTIFICATION AND INTERNAL DIAGRAM

UPD6376CX

VDD

VSS

LRCK

LRSEL/RSI

SI/LSI

CLK

4/8 fs SEL

D.GND

MAIN DAC

13

54

A.GND

SUB DAC

SUB DAC

MAIN DAC

712

A.VDD

14
15

TIMING

16

1
2

GENERATOR

3

N.C.

SHIFT REGISTER

LATCH

D.VDD

11

L.OUT

10

L.REF

R.REF

9

6

R.OUT

8

RE5VA35AA

2

1

OUT

3

1 2 3

1A

2Y

3A

GND

1Y

2A 3

3Y

TC74HC04AP

1

2

4

5

6

7

14

12

11

10

M5218APR PC900V

VCC

VCC

6A13

8

VCC

67

5

6

-

+

-

6Y

+

GND

5A

12

34

12

5Y

9

4A

4Y

8

GND

45

NC

3

— 19 —

BA612

TC74HC174AP

NC

I1
I2
I3
I4
I5

GND

Q1

D1
D2

Q2

D3

Q3

1

R

D

CK

D

CK

D

CK

Q

R

Q

R

Q

CK

D

CK

D

CK

R

D

Q

R

Q

R

Q

2
3
4
5
6
7
8

2SB1274

1
2
3
4
5
6
7

14
13
12
11
10

9
8

NC
O5
O4
O3
O2
O1
NC

CLEAR

GND

S-81350HG

16
15
14
13
12
11
10

9

VCC
Q6
D6
D5
Q5
D4
Q4
CLOCK

1 2 3

2SB1240Q,R

B C E

2SC1740SQ

2SA933SQ

DTA114TS

E C BE C B

— 20 —

PARTS LIST

AT-1

Notes: 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.

FOB Japan

N Item Code No. Parts Name Specification Q N.R.Yen R

Unit Price

Main PCB JCM719-MA1M

N 1 6923 4040 PCB ass'y JCM719-MA1M M140127*1 1 B

LSI101 2011 3325 LSI UPD6376CX 1 A
N LSI102 2012 0021 LSI HD6433298A36P 1 A
N LSI103 2012 0035 LSI TC5316200CP-C106 1 A

LSI105 2011 7434 LSI HG51B155FD 1 A

LSI106 2011 5194 LSI HG52E35P 1 A
N LSI107 2012 0028 LSI SRM2264LC90,10 2 A

IC101 2105 2114 IC, Regulator S-81350HG 1 A
IC102 2114 2891 IC LA4598 1 A
IC103 2114 1421 IC, Photocoupler PC900V 1 A

N IC104 2105 3941 IC RE5VA35AA-TZ 1 A

IC105 2114 1799 IC M5218APR 1 A
IC106 2105 2912 IC HD74HC08P 1 A
IC107 2105 3136 IC HD74HC00P 1 A

Q101 2251 0665 Transistor 2SB1240R.S-TV6-T 1 A

Q102, Q104, 2252 0896 Transistor 2SC1740S-R,S-TP-T

6

Q107/108,

Q121/122

Q103 2251 0651 Transistor 2SB1274-CCC 1 A
Q105 2253 0455 Transistor 2SD1762E,F 1 A
Q106 2250 0574 Transistor 2SA933SQ,R-TP-T 1 A

Q109~116 2259 1883 Digital transistor DTA114TS-TP-T 8 A

D101 2360 2233 Zener diode RD5.1JSB1-T1-T 1 A
D102 2360 0098 Zener diode RD5.1ESB2-T1-T 1 A
D103 2390 0371 Diode DSK10B-BT-T 1 B
D104 2390 1316 Diode SB10-04A3-BT-T 1 B

D105/106, 2390 1344 Diode 1SS133T-77-T

5

D108,

D111/112

D107 2310 7996 Zener diode RD4.7ESB2-T1-T 1 A
D109 2390 1995 Diode RB441Q-T77-T 1 B
X101 2590 1526 Ceramic oscillator EFO-EN2005C4 1 B

X102 2590 1519 Crystal oscillator HC-49U16384 1 B
MC101 2819 5552 Module Capacitor CNB7X102M 1 C
MC102 2845 0168 Module Capacitor CNB8X101K 1 C

FB102~114 2845 3220 Ferrite beads EXC-ELDR35V-T 13 C
EF101~103 3025 0826 EMI filter EXC-EMT222DT-T 3 C

J101 3501 7049 DC jack HEC2305-01-330 1 A
J102 3612 0665 Phone jack YKB21-5006 1 B
J103 3612 0789 Jack YKB21-5010 1 B
J104 3501 4816 DIN jack YKF51-5051 1 B

L101~104, 3841 0539 Inductor ELE-V100KR-T

10

L106~111
N L121 3841 1456 Coil CM08RB01 1 C
N

4317 5522 Blank PCB JCM719-MA1M M140129B-1

1

Volume PCB JCM719-MA2M

2 6923 4050 PCB ass'y M719-MA2M M440151*1 1 B

VR101 2765 1575 Slide volume EWA-MJ0S10B23 1

2-1 3719 2562 Ribbon cable M296D DF5H05130-MM

1C

N 4317 5532 Blank PCB JCM719-MA2M M140129B-2 1 C

Console PCB JCM719-CN1M

N 3 6923 4060 PCB ass'y M719-CN1M M140128*1 1 B

IC303/304 2105 3045 IC HD74HC174P 2 A

Notes: N – New parts

M – Minimum order/supply quantity
R – Rank

— 21 —

A

B

C

A

FOB Japan

N Item Code No. Parts Name Specification Q N.R.Yen R

Unit Price

IC301/302 2114 3318 IC BA612 2 A

LED301~309, 2370 0343 LED LN28RPX-(TT)

LED311

LED309/310 2370 0959 LED LN882RPX-(TT) 2 C

N LED312 2370 1141 LED SL-9352-60 1 C

D301~368 2390 1344 Diode 1SS133T-77-T 68 C

3-1 3719 4235 Ribbon cable M711C DF5H12120-MM 3 C

N 4317 5540 Blank PCB JCM719-CN1M M140130-1 1 C

LED PCB JCM719-CN2M

N 4 6923 4070 PCB ass'y M719-CN2M M340168*1 1 B
N 2370 1148 LED LN28RPH(V)-(TA9) 27 C
N 4317 5550 Blank PCB JCM719-CN2M M140130-2 1 C

Keyboard PCBs

N 5 6923 6940 PCB ass'y M617T-KY1M M140211*1 1 B

2301 0101 Diode 1S2473-T-77-T 64 C
N 5-1 3719 4557 Ribbon cable DF5H16200-MM 1 C
N 4317 5560 Blank PCB M617T-KY1M M140200-1 1 C
N 6 6923 6950 PCB ass'y M617T-KY2M M140212*1 1 B

2301 0101 Diode 1S2473-T-77-T 58 C
N 6-1 3719 4564
N 4317 5570 Blank PCB M617T-KY2M M140201-1 1 C

Bender

2765 1141 Volume RK1631110-50KB 1 C

Mechanical Parts

N

N

N 13 6923 4300 Rubber button 711C M312124-2
N
N

N
N

N 26 6923 4410 Bender knob M340169-1 1 C

N 27 3719 4536 Ribbon cable M719F DF5H03095-35353535 1 C
N 28 6922 3925 Upper case sub ass'y M111732E*2 1 C

7 6923 4250 Display plate 719 M340042-1 1
8 6921 5040 Slide knob M311860-1

9 6923 4290 Panel 719 M140037-1 1
10 3831 0357 Speaker 1221AF
11 6922 3830 Rubber button 711A M312122-1
12 6922 3840 Rubber button 711B M312123-1

14 6923 4310 Rubber button 711F M211727-2 1
15 6923 4320 Rubber button 711E M312126-2 1
16 6922 2680 Rubber button 710D M312082-2
17 6922 3870 Rubber button 711D M312125-1
18 6922 2660 Rubber button 710C M312088-1
19 6923 4350 Rubber button 719A M340038-1 1
20 6923 4360 Rubber button 719B M340039-1 1
21 6922 2840 White key set CEGB M111723-1
22 6922 2860 White key set DFAS M111725-1
23 6922 2850 White key set DFA M111724-1
24 6922 2740 Black key set 10P M111726-1
25 6922 2750 Black key set 5P M111726-2

6911 5241 Bender chassis A M31487A-1 1 C
6911 5250 Bender chassis B M41946-1 1 C
6911 5260 Bender spring M41949-1 1 C

28-1 6902 6140 Battery spring 90 M41226-1 1 B
28-2 6903 2150 Battery spring B M41330-1 1 B
28-3 6922 2810 Lower key stopper 710 M412287-1 1 C
28-4 6922 2820 Upper key stopper 710 M412286-1 1 C
28-5 6922 4480 Key damper 710 M412324-1 1 C

Notes: N – New parts

M – Minimum order/supply quantity
R – Rank

Ribbon cable DF5H17200-MM

— 22 —

9

1C

1

2
1
1
1

1
2
1

5
1A
4A
2A
1A

C

C

B

C

B
B
B
B
B
B
B
B
B
B
B
A

FOB Japan

N Item Code No. Parts Name Specification Q N.R.Yen R

Unit Price

29 6922 2761 Key contact rubber LT-CB M211704A-1 4 A
30 6922 2771 Key contact rubber LT-CS M211705A-1 1 A

31 6922 2631 Bottom plate 710 M211706A-1 1 C
N 32 6918 1636 Battery cover M311164F*1 1 B
N 6923 4280 Rating plate M312163-2 1 C

Accessory

6920 8680 Dust cover 590 M311784-1 1 B
6920 8691 Music stand 590 M311760A-1 1 B

Notes: N – New parts

M – Minimum order/supply quantity

R – Rank

Description of Capacitors

A general description of capacitors is shown in the following table.
The description consists of Type, Value, Rated Voltage and Tolerance.
When you need a capacitor, please find a subsutitution in your country by yourselves referring to the
description.

Ref. No of Capacitor Description

C101, C107, C125, C211 Electrolytic, 16 V, 470 µF, +/-20%
C110, C153 Electrolytic, 6.3 V, 220 µF, +/-20%
C103, C104, C113, C114, C121, C137~C139, C145, C167, C171, C193,
C197
C108 Electrolytic, 16 V, 10 µF, +/-20%
C152, C162 Electrolytic, 50 V, 1 µF, +/-20%
C111, C182 Electrolytic, 6.3 V, 470 µF, +/-20%
C102, C124, C126, C134, C159~C161 Electrolytic, 6.3 V, 100 µF, +/-20%
C123, C127 Electrolytic, 10 V, 100 µF, +/-20%
C144, C165 Semiconductive, 16 V, 2200 pF, +/-10%
C147, C164 Semiconductive, 16 V, 0.033 µF, +/-10%
C130, C131 Semiconductive, 16 V, 0.047 µF, +/-10%
C128, C129, C154, C174 Semiconductive, 16 V, 0.01 µF, +/-10%
C118, C119 Semiconductive, 16 V, 0.018 µF, +/-10%
C140, C155, C166, C170, C175~C179, C181, C185, C186, C188, C189,
C192, C194~C196, C198, C200
C105, C120, C132, C133, C135, C136, C141, C142, C146~C150, C163,
C172, C173, C180, C184, C187, C212~C214
C122, C199 Ceramic, 50 V, 1000 pF, +/-10%
C168 Ceramic, 50 V, 0.01 µF, +/-20%
C191 Semiconductive, 16 V, 33 pF, +/-10%
C156, C157 Semiconductive, 16 V, 4 pF, +/-0.5 pF
C190 Semiconductive, 16 V, 22 pF, +/-10%
C116, C117 Mylar, 50 V, 0.047 µF, +/-10%
C112, C115 Electrolytic, 10 V, 1000 µF, +/-20%

Electrolytic, 10 V, 22 µF, +/-20%

Ceramic, 50 V, 0.1 µF, +80/-20%
Ceramic, 50 V, 100 pF, +/-10%

— 23 —

Description of Resistors

A general description of resistors is shown in the following table.
The description consists of Type, Value, Rated Wattage and Tolerance.
When you need a resistor, please find a subsutitution in your country by yourselves referring to the
description.

Note:
All resistors are carbon film, 1/5 watt, +/-5% otherwise specified.

Ref. No of Resistor Description

R107, R137, R145~R147, R150, R163, R164, R168~R170, R189 1 KΩ
R102, R103, R133, R135, R142 220 Ω
R220~R230 330 Ω
R132, R143, R159, R185, R292 10 Ω
R115, R116, R127, R139~R141, R149, R158, R166, R171~R173,
R186~R188, R206, R208~R211, R213, R215
R175, R212, R214 100 KΩ
R105, R138, R148, R161, R274, R293, R295 10 KΩ
R110, R291 22 Ω
R117, R118 3.3 Ω
R111~R114 82 Ω
R125, R126, R160 4.7 KΩ
R207 1.5 KΩ
R134 2.2 KΩ
R136 270 Ω
R106, R108, R151~R157, R165, R251~R273, R275~R283 470 Ω
R104, R294 47 KΩ
R178~R184, R218, R219, R231~R250 56 KΩ
R216 1 MΩ
R174, R176, R177, R192~R199 33 KΩ
R123, R124, R130, R131 15 KΩ
R128, R129 5.6 KΩ
R217 560 Ω
R162, R167 18 KΩ
R190, R191, R200~R205 33 Ω
R120, R121, R144 47 Ω

100 Ω

— 24 —

8-11-10, Nishi-Shinjuku
Shinjuku-ku, Tokyo 160, Japan
Telephone: [phone]

May, 1995