Sony SEQ-300 - Safety Check-Out; Leakage Test Procedure

MODEL NO.
SEO.3OO
GRAPHIC EOUALIZER
SERIAL
NO.
MADE IN
JAPAN
MODEL IDENTIFICATION
-
Specification
Label
on Jack
Plate
-
US, Canadian model: AC
120V
60Hz 5W
AEP
model:
AC22OY
-50/60H2
5W
UK
model:
AC 24OV
-50/60H2
5W
E model: AC 110-120V122O-24oV
-50/60H2
5W
SAFETY
CHECK.OUT
After
correcting the
original
service
problem,
perform
the
fo[owing
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.
l. A commercial leakage
tester, such
as
the
Simpson
229
or RCA WT-540A.
Follow
the
manufacturers'
instructions
to
use these
instru-
ments.
A
battery-operated AC milliammeter.
The Data
Precisign
245
digital
multimeter is suitable
for
this
job.
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)
2.
3.
To
Exposed
Metal
Parts
on
Set
0-15pF
AC
|Æltmeter
(o.75V)
ig.
A.
Using
an
AC
voltmeter to chæk AC
leakage.
-2-