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TC- W301 / W306
:
SERVICING
NOTE
FOR TC-W301
{To supply B+ voltage ]
When this model alone operates, connect the unit
to the regulated DC power supply, since power of this
model is fed from TA-AX301.
5-pin
DC
input connector
®
12V
to regulated dc
power
supply
SAFETY-RELATED
COMPONENT
WARNING!!
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
AU
COMPOSANT
AYANT
RAPPORT
A LA SECURITE!
LES COMPOSANTS IDENTIFIES PAR UNE MARQUE /\
SUR LES DIAGRAMMES SCHEMATIQUES ET LA LISTE
DES
PIECES SONT CRITIQUES
POUR
LA SECURITE
DE
FONCTIONNEMENT.
NE REMPLACER
CES COM-
POSANTS
QUE
PAR
DES PIECES SONY
DONT LES
NUMEROS
SONT
DONNES
DANS
CE
MANUEL
OU
DANS LES SUPPLEMENTS PUBLIES PAR SONY.
of TC-W301
from
TA-AX301.
SAFETY
CHECK-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 meta! part to
earth ground and from all exposed metal parts to any
exposed
metal part having a return to chassis, must
not
exceed
0.5mA
(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-S540A.
Follow the
manufacturers' instructions to use these instru-
ments.
tro
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 0.75 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
AC
voltmeter
{0.75 V)
=
Earth Ground
Using an AC voltmeter to check AC leakage.
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