18
5. Troubleshooting
5-2 Unsatisfactory Cooking
Parts
Cause
Diagnosis
Remedy
Food is
not
heated.
1) Open cathode
of magnetron
Check the terminals with a multimeter to see
if the heater circuit is open.
Replace magnetron.
2) Defective H. V.
Diode
Check the H. V. Diode for continuity in the
reverse and normal directions using meter. If
there is continuity in the reverse direction, the
H. V. Diode may be faulty. (In this event H. V.
Capacitor will be hot)
Replace H. V. Diode.
3) Shorted
magnetron
Connect megger leads to quick-connect
terminal & body of the magnetron if there is
continuity, the magnetron may be fuse will be
blown) faulty. (In this case the main fuse will be
blown)
Replace magnetron.
4) Defective
magnetron
If there is a crack in the magnetron antenna
(dome), the magnetron is defective.
Replace magnetron.
5) Poor contact of
primary interlock
switch
Check if the screws are secured well to the
door hinge. and pressing it ON and OFF
repeatedly.
Replace or adjust.
6) Open coil of H.
V. Transformer
Check the continuity of primary coil and
secondary coil. If there is no continuity, H. V.
Transformer is defective.
Replace the H. V.
Transformer.
7) Shorted H. V.
capacitor
Check the continuity of capacitor.
If the capacitor shorts, the fuse blows
Replace the H. V.
Capacitor.
8) Monitor Fuse
out
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Replace the Monitor
fuse
5-3 Part Check List
Symptom
Related Parts
Check Points
Remedy
Microwave
cooking does
not work.
H.V.Transformer
1) Check if the primary and secondary coil is open or
shorted.
5HVLVWDQFHRISULPDU\FRLO$SSUR[
5HVLVWDQFHRIVHFRQGDU\FRLO$SSUR[
2) Check if the MGT Heater Voltage is approx. 3.3V AC.
Caution : High voltage !
Replace.
H.V.Capacitor
Check continuity of capacitor between two
terminals with H.V.wire lead removed.
The resistance should be approx. 10MW, it’s failure..
Replace.
H.V.Diode
1) If there is no continuity in forward, direction the
H.V.Diode is open.
2) If there is continuity in reverse direction, it’s shorted.
Replace.
Fan motor
does not
rotate.
Fan motor
Check if the motor coil is open.
Replace.
Summary of Contents for CM1079
Page 3: ...3 1 Precaution ...
