Korg DSS-1 - Service Manual

DIGITAL SAMPLING SYNTHESIZER
SERVICE MANUAL
CONTENTS
1. SPECIFICATIONS
2. ERROR MESSAGES
3. MIDI IMPLEMENTATION.
4. STRUTURAL DIAGRAM..
5. CONNECTOR DIAGRAM.
6. BLOCK DIAGRAM
7. CIRCUIT DIAGRAM
8. P.C. BOARD
.. 2 9. SYSTEM EXPLANATION 32
.. 3 10. MAIN CIRCUIT EXPLANATION 39
.. 4 11. CHECK AND ADJUSTMENT
..9 PROCEDURE 43
12 12. REFERENCE DATA 49
13 13. TROUBLESHOOTING GUIDE 59
14 14. PARTS LIST 62
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Korg DSS-1 Specifications

General

Polyphony	8 voices
Keyboard	61 keys
Memory	64 patches
Resolution	12-bit
Storage	Floppy disk
Year Released	1986
Type	Digital
Synthesis Type	Sampling
Oscillators	Digital Samples
LFO	1 LFO
Filter	2-pole low-pass filter
Sampling Rate	32 kHz
Sample Memory	256 kB
Effects	Chorus
Outputs	Stereo, headphones
MIDI	In/Out
Envelopes	ADSR

Summary

1. Specifications

3. MIDI Implementation

System Exclusive Message Formats

Data Format Reference

Reference for data formats used in MIDI messages.

9. System Explanation

CPU System Overview

Explanation of the dual CPU system and its functions.

Custom LSI and FDD Explanation

CPU Memory Maps

Software Memory Usage

10. Main Circuit Explanation

KLM-780 CPU Board

Explanation of the KLM-780 CPU board circuitry.

KLM-781 CPU2 Board

Explanation of the KLM-781 CPU2 board circuitry.

KLM-782 Tone Generator

Explanation of the KLM-782 Tone Generator section.

KLM-783 VCF;VCA Sections

KLM-786 Power Supply Circuit

11. Check and Adjustment Procedure

Power Supply Voltage Checks

Checking and adjusting power supply voltages.

DAC Power Supply Check

Checking and adjusting DAC power supply.

TG Board A;D Check

Checking and adjusting TG board A/D.

Test Procedures (OSC Levels)

Procedures for checking and adjusting OSC 1 and OSC 2 levels.

Test Procedures (VCF;Resonance)

Procedures for VCF fo and Resonance checks/adjustments.

Test Procedures (Noise, Offset, DDL-1 Clock)

Procedures for noise, DC offset, and DDL-1 clock checks.

Test Procedures (DDL Checks)

Procedures for DDL feedback and delay checks.

Test Procedures (DDL Long Delay;Mute)

Procedures for DDL long delay and mute checks.

12. Reference Data

Programmable Floppy Disk Controller

FDC Terminal Description

Data Separator Explanation

GA-1 Terminal Description

GA-2 Terminal Description

13. Troubleshooting Guide

System Startup and Test Mode

Problem 1: LCD Indication Issues

Troubleshooting steps for missing LCD indication.

Problem 2: Mode Progression Issues

Troubleshooting for failure to progress between system modes.

Problem 3: Switch Input Issues

Problem 4: GET Operation Issues

Problem 5: No Sound Output

Troubleshooting for no sound output after system indication.