5. Examine the starting and the
Pull out the power plug, take off the cabinet, discharge the capacitor, measure the resistance value of the primary winding and
the secondary winding of the transformer with a multi meter (FIG.5-10 and FIG.5-9). The resistance value of the primary
winding should be about 2.2 ohm, the secondary winding should be about 130 ohm, otherwise, it indicates the transformer has
broken, and should be replaced by a new one.
(5) If the high voltage diode is OK, then check the forwarding plug of the transformer to see whether it is enough to 120v.If it is
not enough, check the micro-switch of the time and power distributor. Connect the two rod of the multi meter to the 1.2
place of the timer with Rx1k grade. It is normal if the reading is “0” when at cut off condition. If the reading is “ ”,it indicates
the 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 plug of the magnetron and the capacitor have loosed, if it is loosed, pinch it tightly with a
pliers.
Capacitor
Fig.5-11
Transformer
Fig.5-10
Primary winding
If the transformer is normal, then the high voltage capacitor should be checked. Pull out the connecting plug of the capacitor,
and measure it with Rx1 grade of a multi meter, the two rod of the multi meter connect the two polarity of the capacitor. When
they just connected, the reading of the multi meter should be zero, then enlarge to nine mega ohm slowly. Change the rod to
different polarity, the reading repeat from zero to nine mega ohm (FIG.5-11),it means the capacitor is normal. If the indicator of
the multi meter can’t point out from zero to nine mega ohm, 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
replaced by a same model, same capacity one.
If the resistance value of the capacitor’s two pole are “ ”,the capacitor is normal. Then check the earth of the magnetron’s two
filament to see whether they are short-circuited (FIG.5-13).If they are 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. Pull out the two plugs of the switch, Measure it with the Rx1 grade of a
multi meter, the two rod connect the plug 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 multi meter pointed to zero, it indicates the pilot switch has broken, and should
replace it with a new, same model one.
.REPAIRING METHOD OF SEVERAL BREAKDOWN
1. Repair when there occurred large amounts microwave leakage. There are many factors, which may cause microwave leaking.
Following mentioned may be the main cause of microwave leakage:
(1) The door deformed, the hinge loosed or damaged that caused the door can not close tightly.
(2) The door pressing cover or the embed piece damaged or come off.
(3) Obvious damage or uneven of the oven.
4-3
