micro
switch
has
broken, and the
timer
should be replaced by a new one. If
all
the above examination shows
normal
,then
check whether the terminal
pług
of the magnetron and the capacitor have loosened, if it is loosened,
pinch it tightly with a pliers.
5.2.5
EXAMINE
THE
STARTING
AND THE 8A
FUSE
OF
THE
MICROWAVE
OVEN.
Puli
out the power
pług,
take
off
the cabinet, discharge the
capacitor,
measure the resistance value of the
primary
winding and the secondary winding of the transformer with an
avometer (FIG.5 - 10 and FIG.5 - 9). The resistance value of
the primary winding should be about 2.2 ohms, the secondary
winding should be about
130
ohms.
Otherwise,
it indicates the
transformer has broken, and should be replaced by a new
one.
If the transformer is normal, then the high voltage capacitor Fig. 5-8
should be checked.
Puli
out the connecting
pług
of the
capacitor,
and measure it with
R*1
grade of an avometer, the
two rods of the avometer connect the two polarity of the capacitor. When they just connected, the reading of the
avometer should be zero, then increases to nine megaohm
slowly. Change the rod to
different
polarity, the reading repeat
from zero to nine megaohm (FIG.5 - 11), it means the
capacitor is normal. If the
indicator
of the avometer can't point
out from zero to nine megaohms, it indicates the high voltage
capacitor has broken, and should be replaced by a new one.
If it is normal
between
the two pole of the capacitor, then the
insulation between the capacitor pole and the cabinet should
be measured with
RxlOK
grade of an avometer. The
resistance value should be
"°°"
(FIG.5 - 12). If it is
short
circuited or have a number reading, it indicates that the
capacitor has been punctured or electricity leaked, and should
be replaced by a same model, same capacity one.
secondary winding
Fig. 5-9
transformer
primary winding
Fig. 5-10
Fig. 5-12
magnetron
If the resistance value of the capacitor's two pole
arę
"°°"
,
the capacitor is normal. Then check the
earth
of the
magnetron's two filaments to see whether they
arę
short -
circuited (FIG.5 - 13). If they
arę
short - circuited and the
filament strikes the
shell
of the magnetron, it indicates the
magnetron has broken, and should be replaced by a new,
same model one.
If the magnetron is
also
normal,
then test the pilot switch.
Puli
out the two
plugs
of the switch. Measure it with the
R*1
grade of avometer, the two rod connect the
pług
of the
switch,
the resistance value should
be"°°"
(FIG.5 - 8).
Then press down the pilot switch with a screwdriver, if the
reading of the avometer pointed to zero, it indicates the pilot
switch has broken, and should replace it with a new, same
18
Fig. 5-13
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