Sharp R-8R51 - Page 20

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1 AREIBY
TEST PROCEDURES (CONT'D)
Ly
ie
PROCEDURE
LETTER
COMPONENT TEST
LIVE TEST FOR MOTOR WINDINGS
CAUTION:
The
following
procedure
requires
the
oven
to
be
connected
to
the
s
pply
and
should
only
be
used
if
the
relevant
“cold”
checks
for.the
motor
un-
der
test
are
inconclusive.
1. CARRY OUT 3D CHECKS
2.
Disconnect
the
leads
from
the
primary
of
the
power
transformer,
Make
sure
that
the
jeads
remain
isolated
from
other
oven
components
and
chassis.
(Use
insulation
tape
if
necessary.
)
test procedure or pictorial diagram for the correct terminal numbers.) _
Arrange
the
meter
in
a
position
where
it
can
be
read
during
the
test.
(Do
not
touch
the
meter,
meter
leads
Or
oven
Circuitry
while
the
oven
is
active.)
Close the oven door.
Set
the
relevant
timer
for
about
three
(3)
minutes,
set
the
power
level
to
HIGH
and
push
the
START
button.
7.
Note
the
reading
on
the
meter
and
carefully
observe
the
motor
under
test
to
see
if
it
is
turning.
8.
CARRY
OUT
3D
CHECKS
9
1
-3._-Connect.a-voltmeter;setto250V_AG-across
the-motor
terminals—-(Refer
to
the
relevant
motor.
4
iad
. Remove test meter leads.
0. Reconnect the leads to the primary of the power transformer.
If
a
reading
of
line
voltage
was
obtained
(step
7)
but
the
motor
was
not
turning
then
it
is
faulty
and
should
be
replaced.
{f
the
meter
indicated
that
no
supply
was
present
then
the
wiring
to
the
motor
should
be
checked
for
continuity.
MONITOR RESISTOR AND SURGE RESISTOR TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the monitor resistor or surge resistor.
Using an ohmmeter and set on a low range.
Check
between
the
terminals
of
the
monitor
resistor
or
surge
resistor
as
described
in
the
follow-
ing table.
Table: Resistance
[Rewsor «dC Rentonce
Approx. 3.60
Approx. 100
If
incorrect
readings
are
obtained,
replace
the
monitor
resistor
or
surge
resistor
CARRY
OUT
4R
CHECKS.
NOISE FILTER TEST : a, WaT
CARRY
OUT
3D
CHECKS
pam
rr
ee A2 Cy Al: 10M ohm £ 20%
Disconnect
the
leads
from
the
terminals
F8.3A
Be
ee
of
the
noise
filter.
Using
an
ohmmeter,
ee
ee
check
between
the
terminals
as
described
ee
ee
in
the
following
table.
MEASURING
POINTS
INDICATION
OF
OHMMETER.
Between N and L . Approximately 680kN
Between terminal N and WHITE _ Short circuit
Between terminal L and RED Short circuit
If
incorrect
readings
are
obtatned,
replace
the
noise
filter
unit.
CARRY
OUT
4R
CHECKS
18