11-2 Unsatisfactory Cooking
Parts
Cause
1) Open cathode of
magnetron
2) Defective
H. V. Diode
3) Shorted
magnetron
4) Defective
Food is
magnetron
not heated.
5) Poor contact of
primary interlock
switch
6) Open coil of
H. V. Trans-
former
7) Shorted H. V.
capacitor
8) Monitor fuse
blown out
11-3 Part Check List
Symptom
Related Parts
H.V.Transformer
Microwave
cooking does
not work.
H.V.Capacitor
H.V.Diode
Fan motor
does not
Fan motor
rotate.
Diagnosis
Check the terminals with a multimeter to see
if the heater circuit is open.
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)
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)
If there is a crack in the magnetron antenna (dome),
the magnetron is defective.
Check if the screws are secured well to the door hinge.
and pressing it ON and OFF repeatedly.
Check the continuity of primary coil and secondary
coil. If there is no continuity, H. V. Transformer is
defective.
Check the continuity of capacitor.
If the capacitor shorts, the fuse blows
Check the monitor fuse (on the noise filter)
1) Check if the primary and secondary coil is open or shorted.
* Resistance of primary coil: . 1.94
Resistance of secondary coil: Approx. 139
2) Check if the MGT Heater Voltage is approx. 3.3V AC.
Caution : High voltage !
Check continuity of capacitor between two
terminals with H.V.wire lead removed.
The resistance should be approx. 10M Ω , it's failure..
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.
Check if the motor coil is open.
37
Check Points
Approx
Remedy
Replace magnetron.
Replace H. V. Diode.
Replace magnetron.
Replace magnetron.
Replace or adjust.
Replace the
H. V. Transformer.
Replace the
H. V. Capacitor.
Replace the
Monitor fuse
Remedy
Replace.
Replace.
Replace.
Replace.