Onkyo A 7040 Service Manual

Page 1

ONKYO® SERVICE MANUAL

SUPER SERVO OPERATION
INTEGRATED STEREO AMPLIFIER
MODEI. A-704O

TABLE OF CONTENTS

ITEM PAGE
Specifications 2
Service procedures 2
Precautions 2
Block diagram 3
Circuit description 4
Exploded view 5
Component location 5
Pre, and main ampi p.cib. View 7
Schematic diagram 9
P.c.bV parts list 1 1
Packing procedures 12

ONKYO®
IIIIIIIII BIIMPIIIIIIIIS

SERIAL NO. 301

Page 2

SPECIFICATIONS

Power Output:

Total Harmonic
Distortion:

IM Distortion:

50 watts per channel, min. RMS,
at 8 ohms both channels driven,
from 20 Hz to 20 kHz, with no
more than 0.026% total harmonic
distorition.

0.026% at rated power
0.02% at I watt output
0.026% at rated power

(60sz 7kHz=4:l) 0.02% at 1 watt output

Frequency Response:
RIAA Deviation:
Damping Factor:
Input Sensitivity and
Impedance:

Phono Overload:

Tone Control
BASS:
TREBLE:

High Cut Filter

15 ~ 50,000 Hz (11 dB)
20 ~ 20,000 Hz (10.5 dB)
45 at 8 ohms

PHONE 1 & 2: 2i5mV, 50 koltms
TUNER: lSOmV, 50 kohms
TAPE PLAY 1 & 2:

lSOmV, 50 kohms
l70mV RMS. at lkHz, 0.026% THD

110 dB at 1001-12
110 dB at 10 kHz
6kHz (6 dB/oct.)

SERVICE PROCEDURES

1. VOLTAGE CONVERSION (Universal model)
This model is equipped with a universal power transformer to permit operation at either power source of 110, 120, 220
or 240V AC 50/ 60Hz.
To convert the unit to a different power source voltage, change the plug as illustrated in the drawing below.
CAUTION: DISCONNECT POWER SUPPLY CORD FROM AC OUTLET BEFORE CONVERTING VOLTAGE.

7"

[Edit

VOLTAGE SELECTOR

23s

. )Qr |_Plug

For 110V Operation

2. REPLACING THE SPEAKER PROTECTION FUSE
1) Remove a screw holding the cover and back panel.

2) Replace the fuse with same type and same rating fuses

PREACAUTIONS

Signal to noise ratio:
Loudness: (-40 dB)
Range (Ind. switch)

GENERAL

Power Supply Rating:

Outputs :

Input s:
Semiconductors:
Dimensions :

Weight:

PHONO: 80 dB (IHF A Network)
TUNER: 90 dB (IHF A Network)
+5 dB at 100 Hz

+5 :13 at 10 kHz

x l, x 0.1

AC 120 volts, 60 Hz (120V model)
AC 110, 120, 220 or 240V 50/60Hz
(Universal model)

SPEAKER A & B, PHONES

TAPE REC l & 2

PHONO l & 2

TUNER

TAPE PLAY 1 8!. Z

22 Transistorsf l)0 ICs, l9 yiodes
418 x124H x396(D mm
16-19}? x 4-15/16" x15-5/8"

9.4 kg (20.7 lbs)

Sepecifications and features are subject to change without
notice for improvement.

For 220V Operation

For 120V Operation

For 240V Operation

SPEAKER FUSE

4A-T

R L

1. For continued protection against fire hazard, replace only with same type and same rating fuse.

PARTS NO.
AC fuse 4A (ST-6) 252053 (1 10/ 120V model)
3A-T 252020 (220/240V model)
Speaker protection fuse 4A-T 252014

2. Replacement for power, complementary and driver transistors, if necessary, must be made from the same beta (hpE)
group as the original type.

3. Always disconnect the chassis from power line when soldering.
Turning the power switch OFF is not enough
Power line leakage passing through the heating element may destroy the transistors.

2