Yamaha eq 70

Page 1

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I FRONT PANEL

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SERVICE MANUAL

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IMPORTANT NOTICE

This manual has been provided for me use of authorized Yamaha Retailers and dieir scrvicc personnel. It has been assumed that basic service procedures inheranr to the
industry, and mor: specifically Yamaha Products, are already known and understood by the users, and have merefore not been restatcd.

WARNING:

Failure to follow zppropriam service and safety procedures when servicing this product my result in personal injury, destruction ar expensive components

and failure of the product to perform as specified. For these reasons, we advise all Yamaha praduct owners that all service required should be performed by

an authorized Yamaha Retailer or the appointed service representative.

IMPORTANT: The presentation or sale of this mznual to any individual or firm dues not constitute authorizatian, certification, recognition of any applicable technical

capabilities, or establish 2 principle-agent relationship of any form.

The data provided is believed to b: accurate and applicable in theimitls) 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 subiecl to change without notice or obligation to rctrofit. Should any

discrepancy appear to exist, please contact the disulbuwrs Scrvice Division.

WARNING:
buss in H1: unit (heavy gauge black wires connect to this buss)

Static discharges can destroy expensive components, Discharge any static electricity your body may have accumulated by grounding yourself to the ground

IMPORTANT: Turn the unit OFF during disasscrnbiy and parts replacement. Recheck all work before you apply power to the unit.

l CONTENTS

TO SERVICE PERSONNEL
REAR PANELS 1,
SPECIFICATIONS .....
DIMENSIONS
DESCRIPTION OFOPERATIONS .
iNTERNAL VIEW

DISASSEMBLY PROCEDURES .. 4
BLOCK DIAGRAM . 5
PRINTED CIRCUIT BOARD 6, 7
SCHEMATICDIAGRAM ........................... 8
PARTS LIST 9~12

YAMAHA

YAMAHA CORPORATION HAMAMATSU,JAPAN
3.3K-08II K Printed in Japan 90, 3

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EQ-70

EQ-70

I TO SERVICE PERSONNEL

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Critical Components Information.

Components having special characteristics are marked A
and must be replaced with parts having specifications equal to
those originally installed.

. Leakage Current Measurement (For 120 V Model Only).

When service has been completed, it is imperative that you
verify that all exposed conductive surfaces are properly
insulated from supply circuits.

Meter impedance should be equivalent to 1500 ohm shunted
by 0.15 uF.

Leakage current must not exceed 0.5 mA,

Be sure to test for leakage with the AC plug in both polarities.

I REAR PANELS

O U.C. Models

EQUIPMENT AC LEAKAGE TESTER
UNDER TEST OR EQUIVALENT
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OUTLE INSULATING TABLE

- POLARIZATION

This product is equipped with a polarized alternating current
line plug (a plug having one blade wider than the other). This
plug will fit into the power outlet only one way. This is a
safety feature. (U.C model only)

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