28
6. Troubleshooting
6-2 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
Check the monitor fuse (on the noise filter)
Replace the Monitor
fuse
6-3 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 .
* Resistance of primary coil: . 1.2Ω Approx.
Resistance of secondary coil: Approx. 90Ω
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 .
