Sony ta av 421 service manual

Page 1

TA-AV421

SERVICE MANUAL Canadgg M333

SPECIFICATIONS

AU DIO POWER SPECIFICATIONS Power requirements 120 V AC. 60 Hz
Po m ton 220W (US del)

POWER OUTPUT AND TOTAL HARMONIC we Ws 9' 430 (Can'ggian model)
DISTORTION: Accessories supplied AM loop antenna (1)
With 8-ohm loads, both channels driven, EM wire grime (3) RM U421 (1)

. emu e man er -
from 40 - 29,000 Hz, rated 110 watts per 30"), baneries SUM_3(NS) (2)
channel minimum RMS power, with less Audio signal connecting cord
than 0.9% total harmonic distortion from g2$1g°pfi$xx§ (1';
250 milliwatts to rated output. SYSTEM CONTROL 1 cord (1)

SYSTEM CONTROL 2 cord (1)
SYSTEM CONTROL 3 cord (1)
(For USA model. Ihe SYSTEM
CONTROL 1 and 3 is equipped on
the TC1W421.)
Model only tor Canada:
Headphone MOB-006 (1)
Plug adaptor (1)

Frequency response

PHONO: FtlAA curve

CD. VIDEO: 10 HZ - 50 kHz :3 dB
input

Sensitivity Impedance

. V . .
PHONO 2 5 m 50 10th Design and specifications are subject to change without

CD. VIDEO 250 mV 5o kilohms notice.

Output SPEAKER: Accepts speakers 01 8
to 16 ohms
HEADPHONES: Accepts
headphones with low and high
impedance
Rear:1OW +10 W
(at from off, 8 ohms)
BASS: :10 dB
THEBLE: 16 dB
Dimensions Approx. 430 x 145 x 360 mm
(w/h/d)
(17 x 53/. x 14]. inches)
Weight Approx. 95 kg (20 lb 15 oz) net

INTEGRATED STEREO AMPLIFIER
ONY;

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TA- AV421

TABLE OF CONTENTS

Section Title Page
1. GENERAL .. 3
2. DIAGRAMS

2-1, 1c Block Diagrams ............................. 6
2-2. IC Description -----------

2-3. Circuit Boards Location-

2-4. Printed Wiring Boards-

2-5. Schematic Diagram -Main Section- ......... 17
2-6. Schematic Diagram -Power Section- -------- 21
2-7. Semiconductor Lead Layouts ----------------- 28

3. EXPLODED VIEWS

3- 1.
3- 2.

Overall Section 1 .............................. 24
Overall SectiOn 2 .............................. 25

4. ELECTRICAL PARTS LIST ............. . 26
HARDWARE LIST ................................ 34

MODEL IDENTICATION
- Specification Label -

SONY.

INTEGRATED STEREO AV AMPLIFIER

///fl

MODEL NO. TA-AV421

SERIAL NO,
MADE IN JAPAN

|

US model: AC 120V 60Hz 220W
Canadian model: AC 120V 60Hz 430VA
SAFETY-RELATED COMPONENT WARNINGII

COMPONENTS IDENTIFIED BY MARK A OR DOTTED
LINE WITH MARK A ON THE SCHEMATIC DIAGRAMS
AND IN THE PARTS LIST ARE CRITICAL TO SAFE
OPERATION. REPLACE THESE COMPONENTS WITH
SONY PARTS WHOSE PART NUMBERS APPEAR AS
SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUB«
LISHED BY SONY.

ATTENTION AUCOMPOSANT AYANT RAPPORT
A LA SECURITEI

LES COMPOSANTS IDENTIFIES PAR UNE MARQUE A
sun LEs DIAGRAMMES SCHEMATIOUES ET LA LlsTE
DES PIECES sour calriouEs POUR LA sécumré
DE FONCTIONNEMENT. NE REMPLACER CES COM-
POSANTS QUE PAR oEs PIECES SONY DONT LEs
NUMEROS SONT ooNNEs DANS CE MANUEL ou
DANS LEs SUPPLEMENTS PUBLIES PAR SONY.

SAFETY CHECK-OUT

After correcting the original semce problem,
perform the following safety check before releasing
the set to the customer:

Check the antenna terminals, metal trim, metallized
knobs, screws, and all other exposed metal parts for
AC leakage. Check leakage as described below.

LEAKAGE TEST

The AC leakage from any exposed metal part to
earth ground and from all exposed metal parts to any
exposed metal part having a return to chassis, must
not exceed 0.5 mA (500 microampers). Leakage
current can be measured by any one of three
methods.

I. A commercial leakage tester, such as the
Simpson 229 or RCA WT-54OA. Follow the
manufacturers instructions to use these instru-
ments.

2. A battery-operated AC milliammeter. The Data
Precision 245 digital multimeter is suitable for
this job.

3. Measuring the voltage drop across a resistor by
means of a VOM or battery-operated AC volt-
meter. The limit indication is 0.75V, so
analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa
SH-63Trd are examples of a passive VOM that
is suitable. Nearly all battery operated digital
multimeters that have a 2V AC range are
suitable. (See Fig. A)

To ExpasEd Metal
Parts on Set

AC
/
0.15uF I §I.5kn / 73.}?ea/tfr

'7 Earth Ground

F ig. A. Using an AC voltmeter to check AC leakage.