Revox A77 service manual 2

Page 2

1. CONTENTS

2. GENERAL

21.

Front Panel Rear Panel

3. DlSMANTLlNG

3.1 .
3 2.
3.3

Removal of Housing

Removal of Cover Panel
Removal of Front Panel
Removal of Power vaitch
Removal of Brake Unit
Removal of Reel Motors
Removal of Capaan 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 SWltches)

4. MECHANICS

4,1.

4,2
4.3

4.4.

Headblock

4.1.1. Tape Guides

4.1.2, Head Mounting

Tape Tension

Brakes (Stop i

4.3.1. Brake Torque Measurement
4.3.2, Brake Adjustment

Prefiure Roller

4.4.1. 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 Bearin§
Exchange of Reel Motor Bearings

Lubri oatio n

End-offs pe Switch

5 ELECTRONICS

SWltch Board and VU~Meter Board

Input Amplifier

Record Amplifier

Oscillator

Record Relay

Playback Amplifier

Power Am plifier (Loudspeaker Am plifier)
Power Supply

Drive Control

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

6, ELECTRICAL ADJUSTMENTS AND MEASUREMENTS

6.1.
6.2.

Demagnelizlng

Tape Speed

6.2 1. Pickup Head- Adjustment

6 2 2 Tacho Adjustment

6.2 3, Tacho Adjustment with Cathode-Ray Oscilloscope

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