General Music WK-4 Schematic

4

Index & Warnings

Opening & Keyboard Disassembling Instructions

Assembly & Wiring Connections

Block Diagram, Midi & Controls I/O and Keyboard Int. Pcb Layouts

Midi & Controls I/O, Keyboard Interface & L/R Contact Schematics

Power Amplifier & Supply Schematic, Adjustment Table

Power Amplifier & Supply, Audio/Video Int., Phones & Trackball Pcb Layouts

Controls Panel, Trackball & Dc-Ac Converter Schematics

Controls Panel Pcb Layout & Reverse Layout

Cpu & Sound Generator Schematic (Part 1/2)

Cpu & Sound Generator Schematic (Part 2/2)

Cpu & Sound Generator Pcb Layout

Timing Table

Audio/Video Interface Schematic

Optional Accessories Mounting Instructions

Spare Part List

2
3
4
5
6
7
8
9
10
11
12
13
14
15
16

SERVICE MANUAL

Schematic Diagrams

CODE : 270186

GENERALMUSIC S.p.A. Sales Division: 47048 S.Giovanni in Marignano (RN) ITALY - Via delle Rose, 12 - tel. [phone] - tlx 550555 GMUSIC I - fax [phone]

Notice

Service must be carried out by qualified personnel only.Any tampering carried out by unqualified personnel during the guarantee

For a correct operation of the instrument, after having switched off, be careful to wait at least 3 seconds before switching on again.
To improve the device's specifications, the schematic diagrams may be subject to change without prior notice.

period will forfeit the right to guarantee.

Schematic Notes

All components marked by this symbol have special safety characteristics, when replacing any of these components use only
manufacturer's specified parts.

The (µ) micro symbol of capacitance value is substituted by U. The (Ω) omega symbol of resistance value is substituted by E.
The electrolytic capacitors are 25Vdc rated voltage unless otherwise specified. All resistors are 1/8W unless otherwise specified.

Soldering point.

Male connector.

Female connector.

M/F faston connector.

Test point.

Flag joined with one or more flags with the same signal name inscribed.

Supply voltage.

Logic supply ground.

Analog supply ground.

Chassis ground.

Earth ground.

Observe precautions when handling

ATTENTION

electrostatic sensitive devices

1 1

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1

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1 1

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Opening Instructions

refer to fig. 1
To open the instrument remove the

screws marked by
To separate the keyboard from chassis

remove the screws marked by
(open the instrument before proceed)

To access to the Disk Drive
remove the screws marked by

K

D

Fig. 1

K

K

Keyboard Disassembling Instructions

K

D

D

K

D

D

K

K

K

K

K

K

K

K

Keyboard Exploded View

Sharp Key

Key Return Spring

Remove the key return spring

Natural Key

2

3

Keyboard Base

1

Dual Contact Rubber Strip

Contact board

Unlock the key appling not much strenght
Note: To remove a sharp key before

you must remove a near natural key.

DRW

M. Palanghi 550104

CKD

G. Boccato

APP.

❏ ❏

22

❏

2

❏ ❏

22

DWG#

DISK:

REV:

SCHEMATIC DIAGRAM

OPENING & KEYBOARD

PART:

1/1

40

DISASSEMBLING INSTRUCTIONS

29-10-96

WK4

GENERALMUSIC S.p.A. ITALY

ALL RIGHTS ARE RESERVED, NO COPIES
OR REPRODUCE THIS DOCUMENT WITHOUT
WRITTEN CONSENT BY GENERALMUSIC.

Pitch Board

Left Tweeter

Left Woofer

Left Mylar Strip

Lcd Diplay

Dial Encoder

Right Mylar Strip

Right Tweeter

Right Woofer

Top Chassis

Control Board

Transformer Ass’y

Bottom Chassis

A.C. Filter Board

Transformer

Contrast Adjustment

Main Switch

Phone Board

DC/AC Converter Board

A.C.

A.C.

CONN.2

A.C.

A.C.

After Touch Adjustment

Power Amplifier & Supply Board

CPU & Sound Generator Board

Control & MIDI I/O BoardKeyboard Assembly Floppy Disk Driver

GENERALMUSIC S.p.A. ITALY

3 3

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3

❏

3 3

❏❏

KEYBOARD INTERFACE BOARD (PCB LAYOUT).KEYBOARD INTERFACE BOARD (PCB LAYOUT).

KEYBOARD INTERFACE BOARD (PCB LAYOUT).KEYBOARD INTERFACE BOARD (PCB LAYOUT).

KEYBOARD INTERFACE BOARD (PCB LAYOUT).

MIDI & CONTROLS I/O BOARD (PCB LAYOUT).MIDI & CONTROLS I/O BOARD (PCB LAYOUT).

MIDI & CONTROLS I/O BOARD (PCB LAYOUT).MIDI & CONTROLS I/O BOARD (PCB LAYOUT).

DRW

G. Boccato

CKD

N. Riccobelli

APP.

Pannelli

❏ ❏

44

❏

4

❏ ❏

44

DWG#

DISK:

REV:

550107

40

25/10/96

PART:

PCB#

WK4 BLOCK DIAGRAM

1/1

GENERALMUSIC S.p.A. ITALY

ALL RIGHTS ARE RESERVED, NO COPIES
OR REPRODUCE THIS DOCUMENT WITHOUT
WRITTEN CONSENT BY GENERALMUSIC.

MIDI & CONTROLS I/O BOARD (PCB LAYOUT).

DRW: BOCCATO

APP: PANNELLI REV: 11-12-96

DWG: 315024/088

DISK: 40 PART: 1/1CKD: RICCOBELLI

SCHEMATIC DIAGRAM

Midi & Controls I/O Board, Keyboard
Interface Board (Pcb Layouts)

WK4

GENERALMUSIC S.p.A. Italy

ALL RIGHTS ARE RESERVED, NO COPIES OR
REPRODUCE THIS DOCUMENT WITHOUT
WRITTEN CONSENT BY GENERALMUSIC.

5 5

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5

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