Nikko ALPHA 220 - Service Manual

CONTENTS
SPECIFICATIONS...................................................................
BLOCK DIAGRAM..................................................................
DISASSEMBLY .....................................................................
CIRCUIT DESCRIPTION ...................................,......................
4~6
PARTS LOCATION "
...........
SCHEMATIC DIAGRAM
......................................................
.., 8
C. BOARD ..................................................................
ALIGNMENT...................................................................
POWER TRANSISTORS MOUNTING ASSEMBLY .......................................
PARTS LIST...................................................................
SEMICONDUCTOR DATA
TRANSISTORS ...............................................................
FIELD EFFECT TRANSISTOR ...................................................
DIODES
, LED'S ............................................,.................
ZENER DIODES "
........
INTEGRATED CIRCUITS .
...................................................... 18

Summary

Specifications

Amplifier Section Specifications

Details continuous power output, distortion, frequency response, and noise ratios for the amplifier.

General Specifications

Covers power requirements, dimensions, weight, and operating temperature.

Block Diagram

Disassembly Procedures

Cabinet Cover Removal

Instructions for removing the main cabinet cover.

Bottom Plate Removal

Steps to detach the bottom access plate.

Front Panel Removal

Procedure for removing the front panel.

Power Transformer Removal

Guide for safely removing the power transformer unit.

Circuit Description

Variable Bias Circuit Operation

Explains the operation of the variable bias circuit for optimized performance.

DC Servo Circuit Function

Details the DC servo circuit for drift suppression and stability.

Parts Location Guide

Hi-fT Power Transistor Description

Describes the characteristics and construction of high-frequency power transistors.

Schematic Diagram

P.C. Board Layout (Bottom View)

Alignment Procedures

Test Equipment Setup

Outlines the necessary test equipment and connections for alignment.

Circuit Adjustment Notes

Provides critical notes and precautions for performing circuit adjustments.

Power Transistors Mounting Assembly

Repair Service Precautions

Offers essential safety and repair guidelines for technicians.

Parts List

Semiconductor Data

Transistor Data

Lists electrical characteristics and specifications for various transistors.

Diode and Zener Diode Data

Provides data for diodes, LEDs, and Zener diodes used in the unit.

Integrated Circuit AN6552 Details

Details the specifications and terminal guide for the AN6552 integrated circuit.

Nikko ALPHA 220 Specifications

General

Power output	120 watts per channel into 8Ω (stereo)
Total harmonic distortion	0.008%
Input sensitivity	1V
Signal to noise ratio	100dB
Dimensions	483 x 133 x 368mm
Weight	14.5kg