Revox A 77 Service Manual 3

Page 1

Service Manual

Page 2

1. CONTENTS

2. GENERAL

2.1.

Front Panel Rear Panel

3. DISMANTLING

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

3.10.
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 ol Power Transfomer
Removal of Amplifier Cards
Removal of Potentiometer
Removal of Switch Board
Removal of Frame ( Removal oi Rotary Switches)

4. MECHANICS

4.1.

4.2.
4.3.

4.4.

4.5.

4.6.
4.7.
4.3.

Headblock

4.1.1. Tape Guides

4.1.2. Head Mounting

Tape Tension

Brakes ( Stop 1

4.3.1. Brake Torque Measuremem

<3. 2. Brake Adjustment

Pressure Roller

4.4.1. Pressure Meaurement

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

4.5.1. Removal of Capstan Axis. Ball Bearings
Exchange of Heel Motor Bearings
Lubricatinn

End-oif-Tape Switch

5. ELECTRONICS

5.1.
5.2.
5.3.
5.4.
5.5.
5.6.
5.7.
5.8.
5.9.

5.10.

Switch Board and VU-Meter Board

input Amplifier

Record Amplifier

Oscillator

Record Relay

Playback Amplifier

Power Amplifier ( Loudspeaker Amplifier)
Power Supply

Drive Control

5.9.1. Photoelectric Endof-Tape Switch
Speed Regulation, Capstan Motor

6. ELECTRICAL ADJUSTMENTS AND MEASUREMENTS

5.1.
6.2.

Demagnetizing

Tape Speed

62.1. Pick-up Head - Adjustment

6.2.2. Tacho Adjustment

6.2.3. Tachci Adjustment with Cathoderfiay Oscilloscope

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