Pioneer SA-420 Service Manual

o
o
(D
rrloNeerl'
i".lil
ORDER NO.
ART-
646-O
STEREO
AMPLIFIER
a
a
o
CONTENTS
SPECIFICATIONS
FRONT PANEL
FACILITIES
BLOCK
DIAGRAM
PARTS
LOCATION
EXPLODED
VIEW
P.C.
BOARDS CONNECTION
DIAGRAM.
. . . .
SCHEMATIC DIAGRAM
8.
ELECTRICAL
PARTS
LIST
.
.......
13
9.
PACKING
14
10.
ADJUSTMENT
15
nÉclace
t6
AJUSTE
17
ADDITIONAL
SERVICE MANUAL FOR YP,
AND
S TYPES
19
MODEL
SA-420
COMES
IN FIVE
VERSIONS
DISTINGUISHED
AS
FOLLOWS:
This service
manual
is
applicable
to
the KU type
(pp.
1
-
17!
,
YP
and
Stypes
(pp.
19
-211.
When
repairing
the HE,
HB
types,
please
see the
additional
service manual
(ART-647).
For the
circuit
description,
please
refer to the
supplement
of modef
SA-720
service manual
(ART-76S1.
Ce manuel
d'instruction
se
refère
au mode
de
régtage,
en français.
Este
manual de
servicio
trata
del
método de
ajuste escrito
en espafiol.
1.
2.
3.
4.
5.
6.
7.
2
3
4
5
6
I
11
Type
Voltage
Remarks
KU
12OV only
U.S.A.
model
s
110V, 120V,22OV
and
2zl0V
(Switchabtel
General export
model
YP
24OV
only
Australia
model
HE
22OV
and 2r(lv
(Snitchablel
Europe
model
HB
22OY
and
240V
(Switchablel
United
Kingdom
model
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PIONEEFf
ELECTFIEDNIC
CCIFIPCIFIATICIN
4-1
,
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't-chome,
Mesu.o-ku,
Tokyo 1æ. J6pên
1J.3. FICINEEFI ELECTFIChfICB
OCIFIPCIFIATICIÀ|
85 Oxfond Dniwe, Moonâchie. New Jensey O7O74,
USA
FICINEEFI
E|-ECTFICINIC
(EIJCIC'PE!
N.V. Luichagen-Haven
g,
2O3O
AnÈwe.p, E}elgium
PlCrf\fEÉEl
ELECTFICINICÉi AIJEITEIALIA
PTY.
LTE.
178-184 Elounda.v
F|oad.
Elîaeside. Vctonia 3195.
AusÈna,je
YL
oAPR.1981
Printed in
lapan

Pioneer SA-420 Specifications

General

Type	Stereo Amplifier
Power Output	20 watts per channel into 8Ω (stereo)
Frequency Response	20Hz to 20kHz
Total Harmonic Distortion	0.05%
Input Sensitivity	2.5mV (MM), 150mV (line)
Dimensions	420 x 92 x 256mm
Weight	5.4kg
Damping factor	30
Speaker load impedance	4Ω to 16Ω
Channel Separation	55dB (MM), 60dB (line)
Signal to Noise Ratio (line)	95dB
Signal to Noise Ratio	95dB (line)
Signal-to-Noise Ratio	76dB (MM), 95dB (line)

Summary

Front Panel Features

Power Switch Operation

Controls the power supply to the amplifier. Depress to turn on, release to turn off.

Volume Control Operation

Adjusts the overall output level to speakers and headphones. Minimum at 0, increases clockwise.

Specifications Overview

Amplifier Technical Details

Details continuous power output, harmonic distortion, and frequency response characteristics.

Parts Location Guide

Electrical Parts List

Resistor Component List

Details resistors, including type, part number, and symbol.

Semiconductor Component List

Lists transistors and ICs with their part numbers and corresponding symbols.

Schematic Diagrams

Equalizer Amplifier Schematic Detail

Detailed schematic of the equalizer amplifier section with component values.

Power Amplifier Schematic Detail

Adjustment Procedures

Idle Current Adjustment Procedure

Procedure to set the idle current for the amplifier, including test points and voltage checks.

Contrast of Miscellaneous Parts

Electrical Parts Contrast

Lists electrical components like transformers, fuses, switches, and sockets for various models.