SERVICING
NOTES
SAFETY-RELATED COMPONENTWARNING!!
coMpoNENTs
TDENTIFIED
By MARK
I on oorreo
L|NE
W|THr,Aenr
I oN THE
SCHEMATTCDTAGRAMS
AND IN THEPARTS
LISTARE
CRITICALTOSAFE
OPERATION. REPLACE
THESE
COMPONENTSWITH
SONY PARTSWHOSEPART NUMBERS
APPEAR
AS
SHOWN
IN THISMANUAL OR IN SUPPLEMENTSPUB.
LISHEDBY SONY.
ATTENTION
AU COMPOSANTAYANT RAPPORT
À la sÉcunrrÉr
LEscoMposANrsrDENTrrrÉs
pan
uruenaenoue
I
suRLEs
DTAGRAMMEs
scxÉuartouEsETLA
LtsrE
oes prÈces
soNT
cntrlouEspouR
le sÉcuntrÉ
DE FONCTIONNEMENT. NE REMPLACER CES COM.
posANTs
ouE pAR
oes ptÈces
soNy DoNTLEs
ruuruÉnos
soNT DoNNÉs
oeus cE MANUEL
ou
DANSLEssuppr-Émeruts
pugulÉs
pAR
soNv.
SAFETY
CHECK.OUT
After correcting the original service
problem,
perform the following safety checkbeforereleasing
the
setto thecustomer:
Checktheantennaterminals,
metaltrim,
'tnetalli'g4"
knobs,screws,
andall other exposed
metalpartsfor
AC leakage.
Check
leakageas
described
below.
LEAKAGE
TEST
The
AC leakage
fromanyexposed
metal
part
to
earth
ground
and
from
allexposed
metal
parts
to
any
exposed
metalpart having
a return to chassis,
must
not exceed
0.5mA (500 microampers).
Leakage
current can be measured
by any one of three
methods.
I. A commercialleakage
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.
lvteasuring
the voltagedrop across
a resistorby
means
of a VOM or battery-operated
AC volt-
meter. The "limit" indication is 0.?5V, so
analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa
SH-63Trd are examples
of a passive
VOlvlthat
is suitable. Nearly
all battery operated digital
multimeters that have a 2
V AC range are
suitable. (See
Fig.
A)
o
To Exposed Metat
Parts
on Sea
O.î5
yF AC
wlrmercr
(0.75 V)
ig. A. Using an AC voltmeter to check AC leakage.
? Earth Ground
