Nakamichi 481 Service Manual

Nakamichi 481 Specifications

General

Track System	4-track, 2-channel stereo
Tape Speed	4.76 cm/s
Total Harmonic Distortion	1.0%
Type	Cassette Deck
Tape Type	Type I, CrO2, Metal
Input	50mV (Line)
Channels	2
Inputs	Line
Outputs	Line

Summary

Nakamichi 481 General Information

Control Functions Overview

Identifies and explains the front and rear panel control functions.

Voltage Selector Functionality

Details the voltage selector switch for power input compatibility.

Nakamichi 481 Principle of Operation

Mechanism Details

Explains the tape transport, headblock, and cam operation principles.

Amplifier Circuits

Details playback, record equalizer, and bias oscillation amplifier circuits.

Mechanism Control Circuits

Covers button operation, auto shut-off, and motor control circuitry.

Nakamichi 481 Removal Procedures

Cassette Case Cover Removal

Step-by-step instructions for removing the cassette case cover.

Front Panel Assembly Removal

Procedure for removing the front panel assembly.

Mechanism Assembly Removal

Steps to remove the main mechanism assembly.

Rear Panel, Transformer, and Power Switch Removal

Instructions for removing rear panel, transformer, and power switch.

Nakamichi 481 Mechanical Adjustments

Mechanism Control Cam Adjustment

Detailed procedure for adjusting the mechanism control cam positions.

Tape Speed Adjustment Procedure

Steps for adjusting the tape speed using the capstan motor.

Head Height and Azimuth Alignment

Guide for adjusting playback/record head height and azimuth alignment.

Record Head Stroke Adjustment

Procedure for ensuring the accuracy of the record head stroke.

Nakamichi 481 Electrical Adjustments and Measurements

Adjustment and Measurement Instructions

General instructions and sequence for electrical adjustments.

Playback Frequency Response Adjustment

Steps to adjust playback frequency response.

Dolby NR Circuit Check

Procedure for checking the Dolby NR circuit functionality.

Nakamichi 481 Mounting Diagrams and Parts List

Volume P.C.B. Assembly Parts

Mounting diagram and parts list for the volume PCB assembly.

Control Switch P.C.B. Assembly Parts

Mounting diagram and parts list for the control switch PCB assembly.

Switch P.C.B. Assembly Parts

Mounting diagram and parts list for the switch PCB assembly.

Control P.C.B. Assembly Parts

Mounting diagram and parts list for the control PCB assembly.

Auto Shut-off P.C.B. Assembly Parts

Mounting diagram and parts list for the auto shut-off PCB assembly.

Lamp P.C.B. L Assembly Parts

Mounting diagram and parts list for the left lamp PCB assembly.

Lamp P.C.B. R Assembly Parts

Mounting diagram and parts list for the right lamp PCB assembly.

Nakamichi 481 Mechanism Assembly and Parts List

Synthesis Mechanism Parts

Exploded view and parts list for the synthesis mechanism.

Mechanism Assembly 481 Parts

Exploded view and parts list for the mechanism assembly.

Main Mechanism Chassis Assembly Parts

Exploded view and parts list for the main mechanism chassis.

Head Mount Base Assembly Parts

Exploded view and parts list for the head mount base assembly.

Playback Head Assembly Parts

Exploded view and parts list for the playback head assembly.

Nakamichi 481 Wiring Diagram

Nakamichi 481 Block Diagrams

Amplifier Block Diagram

Block diagram illustrating the audio amplifier section.

Mechanism Control Block Diagram

Block diagram showing the mechanism control logic and components.