Sony SAIF-70 Service manual

SA-IF70

SERVICE MANUAL

• TRANSMITTER • REAR SPEAKER

• This set consist of the following units.

TRANSMITTER EMT-70
REAR SPEAKER SA-IF70S

SPECIFICATIONS

US Model

Canadian Model

AEP Model

E Model

MICROFILM

WIRELESS SPEAKER SYSTEM

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TABLE OF CONTENTS

SAFETY CHECK-OUT

1. SERVICING NOTE

.......................................................... 3

2. ELECTRICAL ADJUSTMENTS ................................. 3

3. DIAGRAMS

3-1. Printed Wiring Board — Transmitter Section —.................. 5

3-2. Schematic Diagram — Transmitter Section — .................... 7

3-3. Printed Wiring Board — Receiver Section — ...................... 9

3-4. Schematic Diagram — Receiver Section — ....................... 11

3-5. IC Block Diagrams.............................................................. 13

4. EXPLODED VIEWS

4-1. Speaker Section................................................................... 14

4-2. Transmitter Section (EMT-70)............................................ 15

5. ELECTRICAL PARTS LIST ........................................16

After correcting the original service problem, perform the follow­ing safety checks before releasing the set to the customer:
Check the antenna terminals, metal trim, “metallized” knobs, screws,
and all other exposed metal parts for AC leaka ge. Check leakage as
described below.

LEAKAGE

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.

1. A commercial leakage tester, such as the Simpson 229 or RCA
WT-540A. Follow the manufacturers’ instructions to use these
instruments.

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 A C v oltmeter. The “limit” indication is 0.75
V, 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 Exposed Metal
Parts on Set

Notes on chip component replacement

• Never reuse a disconnected chip component.

• Notice that the minus side of a tantalum capacitor may be
damaged by heat.

SAFETY-RELATED COMPONENT WARNING !!

COMPONENTS IDENTIFIED BY MARK ! OR DO TTED LINE
WITH MARK ! 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 PUBLISHED BY SONY.

0.15µF

1.5k

Ω

Earth Ground

AC
voltmeter
(0.75V)

Fig. A. Using an AC voltmeter to check AC leakage.

ATTENTION AU COMPOSANT AYANT RAPPORT

À LA SÉCURITÉ!!
LES COMPOSANTS IDENTIFIÉS P AR UNE MARQUE ! SUR
LES DIAGRAMMES SCHÉMATIQUES ET LA LISTE DES
PIÈCES SONT CRITIQUES POUR LA SÉCURITÉ DE
FONCTIONNEMENT . NE REMPLA CER CES COMPOSANTS
QUE PAR DES PIÈCES SONY DONT LES NUMÉROS
SONT DONNÉS DANS CE MANUEL OU DANS LES
SUPPLÉMENTS PUBLIÉS PAR SONY.

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