Yamaha DSP-A595a Service Manual

SERVICE MANUAL
IMPORTANT NOTICE
This manual has been provided for the use of authorized YAMAHA Retailers and their service personnel.
It has been assumed that basic service procedures inherent to the industry, and more specifically YAMAHA
Products, are already known and understood by the users, and have therefore not been restated.
WARNING: Failure to follow appropriate service and safety procedures when servicing this product
may result in personal injury, destruction of expensive components, and failure of the
product to perform as specified. For these reasons, we advise all YAMAHA product
owners that any service required should be performed by an authorized YAMAHA
Retailer or the appointed service representative.
IMPORTANT:The presentation or sale of this manual to any individual of firm does not constitute
authorization, certification or recognition of any applicable technical capabilities,
or establish a principle-agent relationship of any form.
The data provided is believed to be accurate and applicable to the unit(s) indicated on the cover. The research,
engineering, and service departments of YAMAHA are continually striving to improve YAMAHA products.
Modifications are, therefore, inevitable and specifications are subject to change without notice or obligation
to retrofit. Should any discrepancy appear to exist, please contact the distributor's Service Division.
WARNING: Static discharges can destroy expensive components. Discharge any static electricity
your body may have accumulated by grounding yourself to the ground buss in the unit
(heavy gauge black wires connect to this buss).
IMPORTANT:Turn the unit OFF during disassembly and part replacement. Recheck all work before
you apply power to the unit.
100678
AV AMPLIFIER
DSP-A595a
TO SERVICE PERSONNEL ........................................... 1
REMOTE CONTROL PANELS....................................... 1
REAR PANELS ............................................................... 2
SPECIFICATIONS....................................................... 3~4
INTERNAL VIEW ............................................................ 5
DISASSEMBLY PROCEDURES .................................... 5
SELF DIAGNOSIS FUNCTION ................................ 6~17
FACTORY PRESET ...................................................... 18
■ CONTENTS
AMP ADJUSTMENT ..................................................... 19
IC DATA .................................................................. 20~30
DISPLAY DATA ........................................................... 31
BLOCK DIAGRAM .................................................. 32~33
PRINTED CIRCUIT BOARD ................................... 34~47
SCHEMATIC DIAGRAM ......................................... 48~53
PARTS LIST ............................................................ 54~67
REMOTE CONTROL TRANSMITTER ......................... 68

Yamaha DSP-A595a Specifications

General

Channels	5.1
Frequency Response	20 Hz - 20 kHz
Input Impedance	47 kΩ
Signal-to-Noise Ratio	96 dB (CD)
Input sensitivity	200 mV
Surround Sound	Dolby Pro Logic
Weight	9.3 kg
Power output per channel	100 W
Total Harmonic Distortion	0.04%
Dimensions	151 mm

Summary

Service Information and Safety

To Service Personnel

Critical service info, special components, and leakage current measurement procedures.

Important Notices and Warnings

General safety, handling, and disclaimer notices for service personnel.

Remote Control Panels

Chemical Content Warning

Crucial safety notice regarding hazardous materials in components.

Specifications

Dimensions and Selector Warning

Impedance Selector Warning

Safety warning regarding the impedance selector switch usage.

Self Diagnosis Function

Function Purpose and Operation

Explains the purpose and basic operation of the self-diagnosis feature.

Diagnostic Menu Items

Lists the 11 main diagnostic menu items and their submenus.

Diagnostic Program Operation

Starting the Diagnostic Program

Detailed steps for initiating the diagnostic program using front panel keys.

Exiting the Diagnostic Program

Procedures for safely exiting the diagnostic mode.

Diagnosis Function: Analog and DSP

No.1 Analog Through Details

Describes analog input bypass and DSP through modes for MAIN L/R signals.

No.2 DSP Through Details

Describes DSP through modes for various digital inputs.

Diagnosis Function: DSP and AC-3/DTS

No.2 DSP Through (Continued)

Continues detailed explanation of DSP through modes for YSS918 and SRAM.

No.3 AC-3/DTS Through

Describes digital input signal processing for AC-3/DTS.

Diagnosis Function: AC-3/DTS and Pro Logic

No.3 AC-3/DTS Through (Continued)

Details AC-3 status information and Pro Logic operation conditions.

No.4 Pro Logic Details

Explains Pro Logic decoding based on input type and submenu settings.

Diagnosis Function: Speaker Set

No.5 Speaker Set Configuration

Details speaker set configurations for different inputs and their analog switch settings.

Speaker Set Submenu Purposes

Explains the purpose of each speaker set submenu.

Diagnosis Function: Display and Presets

No.6 Display Check

No.7 Manual Test

No.8 Factory Preset

Describes initialization of backup RAM and protection data.

Diagnosis Function: Data Check

No.9 AD Data Check

Explains how to check A/D conversion values for CPU detection (key scan, protection).

Diagnosis Function: MICOM Status

No.10 Status From DSP MICOM

Describes sequential display of DSP microprocessor status data in hexadecimal.

Diagnosis Function: Version Info

No.11 CPU Version/Check Sum

Displays CPU/DSP version, check sum, and port settings for compatibility.

Factory Preset Settings

Input and Effect Level Presets

DSP Program Presets

Set Menu Presets

Amplifier Adjustment

Idling Current Confirmation

Procedure for confirming and adjusting amplifier idling current.

IC Data: Main Microcontroller

IC800 Pin Assignment

IC Data: Main Microcontroller Details

IC800 Pin Functions Part 1

IC Data: Main Microcontroller Details Part 2

IC800 Pin Functions Part 2

IC Data: Sub Microcontroller

IC14 Pin Assignment

IC Data: Sub Microcontroller Details

IC14 Pin Functions Part 1

IC Data: DSP Decoder

IC4 Pin Assignment

IC Data: DSP Decoder Details Part 1

IC4 Pin Functions Part 1

IC Data: DSP Decoder Details Part 2

IC4 Pin Functions Part 2

IC Data: DSP Decoder Details Part 3

IC4 Pin Functions Part 3

IC Data: SRAM and DAC

SRAM IC (IC5) Pin Data

DAC IC (IC7) Pin Data

IC Data: Codec

Codec IC (IC6) Pin Assignment

Block Diagram

Overall System Block Diagram

High-level functional block diagram of the AV amplifier.

Schematic Diagram: Video

Video Selector and Amplifier Schematic

Circuit diagram for the video signal path, selector, and amplifier.

Schematic Diagram: Input

Input Selector and Control Schematic

Circuit diagram for audio input selection and control logic.

Schematic Diagram: Main

Main Amplifier and Regulator Schematic

Circuit diagram for the main power amplifiers and voltage regulators.

Schematic Diagram: Operation

DSP Control and Tone Control Schematic

Circuit diagram for DSP control, tone adjustment, and power supply.

Schematic Diagram: DSP

DSP and Decoder Schematic

Circuit diagram for the DSP, Dolby Digital, Pro Logic, and DTS decoders.

Parts List: Electrical Components

Abbreviations for Electrical Parts