Sony dxah 3750 service manual

Page 2

DXA-H375

SAFETY CH ECK-OUT

After correcting the original service 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-540A. 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 Iimit 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 snitable. Nearly all battery operated digital
multimeters that have a 2V AC range are
suitable. (See Fig. A)

To Exposed Meta/
Parts on Set

A C
/ voltmeter
(0. 75 VI

0.15M [I gum

7" Earth G/ound

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

MODEL IDENTIFICATION
- Model Number Label -

SONY

STEREO CASSETTE DECK AMPLIFIER

WWW

MODEL N0, DXA~H3750

US model: AC: 120V 60Hz 120W

CND model: AC: 120V 60Hz 130W

AEP, IT model: AC: 220-230V~50/60Hz 125W
UK model: AC: 240V~50Hz 270W

OCND: Canadian model
0sz Italian model

SAFETY-RELATED COMPONENT WARNINGII

COMPONENTS IDENTIFIED 8V MARK A OR DOTTED
LINE WITH MAFIK 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 AU COMPOSANT AYANT RAPPORT
A LA SECURITEI

LES COMPOSANTS IDENTIFIES PAR UNE MAROUE A
sun LES DIAGRAMMES SCHEMATIQUES ET LA LISTE
DES PIECES SONT camoues POUR LA SECURITE
DE FONCTIONNEMENT. NE REMPLACER ces COM-
POSANTS our: PAR DES PIECES SONY DONT LES
NUMEROS SONT DONNES DANS cs MANUEL ou
DANS LES SUPPLEMENTS PUBLIES PAR SONY.