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PVM-8041Q/8044Q
SAFETY CHECK-OUT
(US Model
only)
After
correcting the original service
problem, perform
the
following
safety
checks
before releasing
the
set to
the
customer:
1.
Check
the area
of your
repair for
unsoldered or poorly-soldered
connections.
Check
the entire
board
surface for solder splashes
and
bridges.
2.
Check
the interboard
wiring
to
ensure
that
no
wires
are
"pinched"
or contact high-wattage
resistors.
3.
Check
that
all
control
knobs,
shields,
covers,
ground
straps,
and
mounting hardware have been
replaced.
Be
absolutely
certain that
you
have
replaced
all
the insulators.
4.
Look
for
unauthorized replacement
parts,
particularly
transistors,
that
were
installed
during
a
previous
repair
Point
them
out
to the
Customer and
recommend
their
replacement.
5.
Look
for parts
which, though
functioning,
show
obvious
signs
of
deterioration.
Point
them
out
to
the
customer and
recommend
their
replacement.
6.
Check
the
line
cord
for
cracks
and
abrasion.
Recommend
the
replacement of any such
line
cord
to the
customer.
7.
Check
the
condition of
the
monopole
antenna
(if
any).
Make
sure the
end
is
not
broken
off,
and
has
the
plastic
cap
on
it.
Point out
the
danger of impalement on
a
broken antenna
to the
customer,
and
recommend
the
antenna's replacement.
8.
Check
the
B+
and
HV
to
see they are
at
the
values
specified.
Make
sure
your
instruments
are accurate;
be
suspicious of
your
HV
meter
if
sets
always have
low
HV.
9.
Check
the
antenna
terminals,
metal
trim,
"metallized" knobs,
screws,
and
all
other
exposed
metal
parts for
AC
leakage.
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
AC
voltmeter.
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
V
OM
that
is
suitable.
Nearly
all
battery
operated
digital
multimeters
that
have
a
2V
AC
range
are
suitable.
(Sec
Fig.
A)
HOW
TO
FIND
A
GOOD
EARTH
GROUND
A
cold-water pipe
is
guaranteed
earth
ground;
the
cover-plate
retaining
screw on most
AC
outlet
boxes
is
also
at
earth
ground.
If
the
retaining
screw
is
to
be used
as
your
earth-ground,
verify
that
it
is
at
ground by measuring
the resistance
between
it
and
a
coldwater
pipe
with an
ohmmeter.
The
reading should
be
zero
ohms.
If
a
cold-water
pipe
is
not
accessible,
connect
a
60-100
watts trouble
light
(not a
neon
lamp) between
the hot side
of
the receptacle
and
the retaining
screw.
Try
both
slots,
if
necessary,
to
locate the hot side
of
the
line,
the
lamp
should
light
at
normal
brilliance
if
the
screw
is
at
ground
potential.
(See
Fig.
B)
To
Exposed
Metal
Parts
on
Set
AC
voltmeter
(0.75V)
Earth
Ground
Fig.
A.
Using an
AC
voltmeter
to
check
AC
leakage.
O.tSpFy
1
.5kQ
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3
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