Yamaha YST-SW315 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
or 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.
■ CONTENTS
TO SERVICE PERSONNEL .......................................... 2
SPECIFICATIONS / 参考仕様 ........................................ 3
INTERNAL VIEW ........................................................... 3
BLOCK DIAGRAM......................................................... 4
REAR PANELS .......................................................... 4~5
DISASSEMBLY PROCEDURES/分解手順 ............. 6~7
ADJUSTMENTS / 調整 ............................................ 8~10
PRINTED CIRCUIT BOARD .................................. 11~12
SCHEMATIC DIAGRAM .............................................. 13
PARTS LIST ........................................................... 15~23
YST-SW315
100855
P.O.Box 1, Hamamatsu, Japan
SERVICE MANUAL
SUBWOOFER SYSTEM
YST-SW315

Yamaha YST-SW315 Specifications

General

Driver	10" cone
Frequency Response	20 Hz - 160 Hz
Weight	19 kg
Impedance	5 Ohms
Inputs	Line Level, Speaker Level
Outputs	Speaker Level

Summary

Important Notices and Safety Precautions

Service Personnel and Safety

Warns about risks of injury and component damage from improper service, advising authorized personnel.

Data Accuracy and Product Updates

Notes that specifications may change and advises contacting the distributor for discrepancies.

Static Discharge Precautions

Warns about static discharges damaging components and advises grounding.

Service Safety Guidelines

Instructs to turn off power during service and recheck work before applying power.

To Service Personnel

Critical Components and Leakage Current

Covers replacement of critical parts and procedures for leakage current measurement after service.

Chemical Content and Solder Warnings

Warns about lead in solder and chemical hazards in components, providing guidance on lead-free solder.

Specifications

Technical Specifications

Lists detailed technical specifications of the subwoofer, including output power and dimensions.

Internal View

Component Identification

Shows an internal view with numbered components and their respective PCB locations for identification.

Block Diagram

Signal Path and Functional Blocks

Displays the signal flow and main functional blocks of the subwoofer's circuitry.

Rear Panels

U, C, A Models Rear Panel Layout

Illustrates the rear panel connections and features for U, C, and A model subwoofers.

B, G Models Rear Panel Layout

Illustrates the rear panel connections and features for B and G model subwoofers.

R, T, K Models Rear Panel Layout

Illustrates the rear panel connections and features for R, T, and K model subwoofers.

J Model Rear Panel Layout

Illustrates the rear panel connections and features for the J model subwoofer.

Disassembly Procedures

Driver Removal

Details steps for removing the driver unit, including unscrewing and disconnecting.

Front Panel Assembly Removal

Outlines steps to remove the front panel assembly, including unscrewing and disconnecting connectors.

Rear Panel Removal and PCB Check

Rear Panel Assembly Removal

Details steps for removing the rear panel assembly, including unscrewing and disconnecting connectors.

PCB Checking Procedure

Provides instructions for checking the PCB, including reconnecting connectors and placing the unit on a cloth.

Bush Replacement Note

Notes that a specific bush must be replaced with a new one after removing the rear panel assembly.

Adjustments

Power Amp Operation Confirmation

Describes how to confirm power amplifier operation using a signal generator and oscilloscope, checking waveforms at specific points.

Waveform Observation Criteria

Details the normal and abnormal waveform observations for points A and B, including voltage and time settings.

Idling and Auto Standby Checks

Idling Adjustment Procedure

Explains how to perform idling adjustment for amplifier stabilization, including wait times and voltage checks.

Auto Standby Operation Check

Details the procedure to check the auto standby function, including setting the switch and observing LED changes.

Schematic Diagram (Partial)

Power Amplifier Schematic and Test Points

Shows part of the schematic, focusing on the power amplifier and test points.

Printed Circuit Board (Foil Side)

Semiconductor Locations on MAIN PCBs

Lists semiconductor component references and their locations on various MAIN PCBs.

Schematic Diagram

Full Schematic and Component Details

Presents the complete schematic diagram, including pin connection details and part types.

Parts List

Electrical Parts List and Abbreviations

Lists electrical components with their part numbers, descriptions, and abbreviations.

Main PCB Component Lists

Capacitor List (C1-C60)

Details capacitors C1 through C60, including part numbers, types, values, and markets.

Diode and Fuse Lists

Lists diodes and fuses with their part numbers, types, and markets.

Resistor and Relay Lists

Lists resistors and relays with their part numbers, types, and markets.

Mechanical Parts

Exploded View and Part Numbers

Shows an exploded view of the subwoofer assembly and lists mechanical parts with their part numbers and descriptions.

Rear Panel Mechanical Parts

Rear Panel Exploded View and Part Numbers

Shows an exploded view of the rear panel assembly and lists mechanical parts with their part numbers and descriptions.