Revox A 77 Service Manual 2

Page 1

Service Manual

REVox A77

Page 2

1. CONTENTS

2. GENERAL

2.1.

Front Panel Rear Panel

3. DISMANTLING

3.1t
3.2.
3.3.
3.4.
3.5.
3.6.
3.7.
3.8.
3.9.

3110.
3.11.
3.12.
3.13.

Removal of Housing

Removal of Cover Panel
Removal of Front Panel
Removal of Power Switch
Removal of Brake Unit
Removal of Reel Motors
Removal of Capstan Motor
Removal of Control Board
Removal of Power Transformer
Removal of Amplifier Cards
Removal of Potentiometer
Removal of Switch Board
Removal of Frame ( Removal of Rotary Switches)

4. MECHANICS

4.1.

4.2.
4.3.

4.4.

4.5.

4.6.
4.7.
4.8.

Headbloek

4.1.1. Tape Guides

4.1.2. Heed Mounting

Tape Tension

Brakes (Stopl

4.3.1. Brake Torque Measurement
4.3.2. Brake Adjustment

Pressure Roller

4.4.11 Pressure Measurement

4.4.2. Pressure Solenoid Readjustment
4.4.3. Exchange of Pressure Roller
4.4.4. Pressure Lever Readjustment
Capstan Motor

4.5.1. Removal of Capstan Axis, Ball Bearings
Exchange of Reel Motor Bearings
Lubrication

End-of-Tape Switch

5. ELECTRONICS

5.1.
5.2.
53.
5.4.
5.5.
5.6.
5.7.
5.8.
5.9.

5.10.

Switch Board and VU-IVleter Board

Input Amplifier

Record Amplifier

Oscillator

Record Relay

Playback Amplifier

Power Amplifier l Loudspeaker Amplifier 1
Power Supply

Drive Control

5.9.1. Photoelectric End-of-Tape Switch
Speed Regulation, Capstan Motor

6. ELECTRICAL ADJUSTMENTS AND MEASUREMENTS

6.1.
612.

Demagnetizing

Tape Speed

6.2.1. Pickeup Head . Adjustment

5.2.2. Tacho Adjustment

6.2.3. Tacho Adjustment with Cathode-Ray Oscilloscope

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