Aiwa AX-7400 Service Manual

(SERVICE MANUAL)
Set using ISO screws
DATE OF ISSUE 30/10/1977
SPECIFICATIONS
GENERAL
Semiconductors: 1 IC, 1 FET, 47 transistors, 25 diodes &
1 LED
AX-7400EE: 120V/220V
(Switchable) 50/60 Hz
AX-7400UK: AC120V/240V
(Switchable) 50/60 Hz
Power consumption: 205W (MAX)
Dimensions: 420(W) x 150(H) x 360(D} mm
Weight: 9.0 kg
Power source:
FM TUNER SECTION
Frequency ranges: 87 ~109 MHz
Intermediate frequency:
10.7 MHz +0.1 MHz
Frequency scale accuracy:
+150 kHz (88 MHz}
+200 kHz (98 MHz)
+150 kHz (108 MHz)
Noise limit sensitivity: AX-7400EE: (SN26 dB, div 40 kHz)
3+2 dB (88, 98, 108 MHz)
AX-7400UK: (SN30 dB, div 75 kHz,
THD 3%)
7 <10dB (88 MHz)
7< 9B (98, 108 MHz)
Image frequency interference ratio:
45 > 40 dB (98 MHz}
Intermediate frequency interference ratio:
75 > 70 dB (98 MHz)
Muting sensitivity: 26+4dB
Effective selectivity: AX-7400EE: {tune out 300 kHz,
div 40 kHz)
60 > 55 dB
AX-7400UK: (tune out 400 kHz,
div 75 kHz)
65 > 60 dB
Capture ratio: 1.5 +1 dB
Separation: 40 > 35 dB (1 kHz)
SN ratio: 63 > 58 dB {input 60 dB)
AM TUNER SECTION
Frequency ranges: 515~1650 kHz
intermediate frequency:
AX-7400EE: 455 kHz +5 kHz
AX-7400UK: 468 kHz +5 kHz
Frequency scale accuracy:
+20 kHz (600 kHz}
+30 kHz (1000 kHz)
+35 kHz (1400 kHz)
Noise limit sensitivity: 46 < 50 dB (600, 1000, 1400 kHz)
(SN20 dB)
Image frequency interference ratio:
40 > 35 dB (1400 kHz)
Intermediate frequency interference ratio:
32 > 25 (input 74 dB, 1000 kHz)
IF selectivity: +25/—25 +6 dB (1000 kHz)
Tuning hum: 44 > 36 dB {input 74 dB, 1000 kHz)
AGC characteristic: | 50 +5 dB (1000 kHz)
PRE AMP SECTION
<PHONO AMP SECTION>
Sensitivity/impedance: 2.5 mV —52 +2 dB/47 kQ
Gain: 35.5 +1 dB (1 kHz)
Allowable input: 120 > 100 mV (1 kHz 0.5%)
Distortion: 0.4 < 0.5% (input 100 mV>, 1 kHz)
RIAA curve deviation: +0 +0.8 dB (30 Hz~15 kHz)
Separation: 35 ah dB (1 kHz)
SN ratio: 65 2 60 dB
<TAPE-1, AUX SECTION>
Sensitivity/impedance: 150 mV —16.5 +2 dB/470 kQ
Gain: 0 +9 dB (1 kHz)
Distortion: 0.05< 0.1%
Frequency response: +0 yp (99 H2~50 kHz)
—
Separation: 40 an dB
SN ratio: 70 <65 dB
CONTROL MAIN AMP SECTION
Gain: 37.5 +3 dB (1 kHz)
Tone controls: BASS
+8, —7 dB/+6, —5 dB +1.5 dB (100 Hz)
400/200 Hz turnover frequency
TREBLE
+8, —10 dB/+5, —6 dB +1.5 dB (10 kHz)
2.5/5 kHz turnover frequency
Loudness Response: +7 +1.5 dB {100 Hz)
{With volume at -40dB) +4 +1.5 dB (10 kHz)
Continuous power output: 32W + 32W > 30W + 30W (420)
1 kHz {both channels driven) (distortion 0.5%)
Harmonic Distortion: 0.5% < 0.8% (1 kHz, 30W + 30W)
0.05% < 0.1% (1 kHz, 1W + 1W)
27W + 27W > 25W + 25W
(40 Hz~10 kHz, distortion 0.5%)
0.6 < 0.8 mV (482)
Power bandwidth:
Residual noise:
® Specifications and external appearance are subject to change
without notice due to product improvement.

Aiwa AX-7400 Specifications

General

Brand	Aiwa
Model	AX-7400
Category	Stereo Receiver
Language	English

Summary

Specifications

FM Tuner Section

Performance details of the FM tuner section.

AM Tuner Section

Performance details of the AM tuner section.

Preamp Section

Performance details of the pre-amplifier section.

Control Main Amp Section

Performance details of the main amplifier section.

Disassembly Instructions

Top Panel Removal

Steps to remove the top panel for access.

Front Panel Removal

Steps to remove the front panel for access.

Tuner Circuit Board Removal

Steps to remove the tuner circuit board.

Switch Circuit Board Removal

Steps to remove the switch circuit board.

Main Amp/Power Circuit Board Removal

Steps to remove the main amplifier and power circuit boards.

Lamp Circuit Board Removal

Steps to remove the lamp circuit board.

Disassembly Instructions (Continued)

Muting Circuit Board Removal

Steps to remove the muting circuit board.

Control Circuit Board Removal

Steps to remove the control circuit board.

Speaker Switch Circuit Board Removal

Steps to remove the speaker switch circuit board.

Dial Cord Stringing

Dial Cord Stringing Procedure

Guide on how to correctly string the dial cord.

Exploded View-1

Mechanical Parts List

Panel Assembly Parts

List of parts for the main panel assembly.

Front Panel Components

List of parts specific to the front panel.

Cabinet and Related Parts

Parts list for the cabinet and associated components.

Knobs and Buttons

List of control knobs and selector buttons.

Exploded View-2

Electrical Components List

Tuner Circuit Board Components

List of components for the tuner circuit board.

EQ Circuit Board Components

List of components for the EQ circuit board.

Main Amplifier/Power Board Components

List of components for the main amplifier and power board.

Switch Circuit Board Components

List of components for the switch circuit board.

Exploded View-3

Electrical Components List (Continued)

Amp Chassis and Related Parts

List of parts associated with the amplifier chassis.

Antenna and Terminal Parts

Parts for antenna connections and components.

AC Cord and Related Parts

Parts for the AC power cord and connections.

Various Screws and Connectors

List of various types of screws and connectors used.

Accessories and Package Contents

Included Accessories

List of items provided with the unit.

Hardware Nomenclature

Screw and Washer Definitions

Explains different types of screws and washers.

Schematic Diagram

Schematic Diagram (Continued)

Adjustment Procedures

AM-IF Alignment

Steps for aligning the AM Intermediate Frequency.

AM-RF Alignment

Steps for aligning the AM Radio Frequency.

FM-IF Alignment

Steps for aligning the FM Intermediate Frequency.

FM-RF Alignment

Steps for aligning the FM Radio Frequency.

MPX Adjustment

Multiplex (MPX) Adjustment

Procedures for adjusting FM stereo separation.

Adjustment Procedures (Continued)

MPX Adjustment

Procedures for adjusting FM stereo separation.

Level Diagram

Visual representation of signal levels in different sections.

Wiring Diagram-1

Wiring Diagram-1 (Continued)

Wiring Diagram-2

EQ Circuit Board Wiring

Wiring details for the EQ circuit board.

Transistor Circuit Board Wiring

Wiring details for transistor circuit boards.

Main Amplifier/Power Board Wiring

Wiring details for the main amp/power board.

Speaker Selector/Switch Board Wiring

Wiring for speaker selection and switching.

Lamp Circuit Board Wiring

Wiring details for the lamp circuit board.

Wiring Diagram-2 (Continued)

Transistor Circuit Board Wiring

Wiring details for transistor circuit boards.

Muting Circuit Board Wiring

Wiring details for the muting circuit board.

Main Amplifier/Power Board Wiring

Wiring details for the main amp/power board.

Lamp Circuit Board Wiring

Wiring details for the lamp circuit board.

Electrical Main Parts List

Tuner Circuit Board Parts

Component list for the tuner circuit board.

EQ Circuit Board Parts

Component list for the EQ circuit board.

Main Amp/Power Board Parts

Component list for the main amp/power board.

Control Circuit Board Parts

Component list for the control circuit board.

Switch Circuit Board Parts

Component list for the switch circuit board.

Electrical Main Parts List (Continued)

Speaker Switch Board Parts

Component list for the speaker switch board.

Transistor Circuit Board Parts

Component list for the transistor circuit boards.

Fuse Circuit Board Parts

Component list for the fuse circuit board.

Miscellaneous Parts

List of various miscellaneous components.

Muting Circuit Board Parts

Component list for the muting circuit board.

Speaker Terminal Board Parts

Component list for the speaker terminal board.

Antenna Circuit Board Parts

Component list for the antenna circuit board.

Lamp Circuit Board Parts

Component list for the lamp circuit board.

Meter Circuit Board Parts

Component list for the meter circuit board.