P.O.Box 1, Hamamatsu, Japan
SERVICE MANUAL
1 0 1 3 5 6
'16.04
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 specifi cally 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 specifi ed. 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 fi rm does not constitute authorization, certifi cation 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. Modifi cations are, therefore, inevitable and specifi cations
are subject to change without notice or obligation to retrofi t. 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.
Copyright (c) Yamaha Corporation All rights reserved.
This manual is copyrighted by Yamaha and may not be copied or
redistributed either in print or electronically without permission.
Note:
When accepting a repair order from the user, it is recommended to receive the A-670/A-U670 and CD-
NT670/CD-NT670D as a set for the repair work.
MCR-Nx70/MCR-Nx70D
MICRO COMPONENT SYSTEM
NS-BP401/NS-BP301
A-U670/A-670/A-U671
INTEGRATED AMPLIFIER
SPEAKERS
■
CONTENTS
TO SERVICE PERSONNEL ............................................2
SYSTEM COMPOSITION /
.......................3
FRONT PANELS .............................................................5
REAR PANELS ...............................................................7
REMOTE CONTROL PANEL ........................................ 12
SPECIFICATIONS /
....................................... 12
INTERNAL VIEW .......................................................... 15
SERVICE PRECAUTIONS /
........................................... 19
IC DATA .........................................................................28
PIN CONNECTION DIAGRAMS ...................................31
BLOCK DIAGRAM ........................................................33
WIRING DIAGRAMS .....................................................34
PRINTED CIRCUIT BOARDS .......................................36
SCHEMATIC DIAGRAMS .............................................41
REPLACEMENT PARTS LIST ......................................45
REMOTE CONTROL .....................................................68
This service manual is for the A-670/A-U670/A-U671/NS-BP401/NS-BP301. For service manual of the CD-NT670/CD-
NT670D, please refer to the following publication numbers:
CD-NT670/CD-NT670D:
1013 5 3
A
-U670/A
-670/A
-U671/
NS-BP40
1/NS-BP30
1
