Unsatisfactory Cooking; Part Check List - Samsung CM1099 Service Manual

5. Troubleshooting

5-2 Unsatisfactory Cooking

Parts Cause
1) Open cathode
of magnetron
2) Defective H. V.
Diode
3) Shorted
magnetron
Food is
not
4) Defective
heated.
magnetron
5) Poor contact of
primary interlock
switch
6) Open coil of H.
V. Transformer
7) Shorted H. V.
capacitor
8) Monitor Fuse
out

5-3 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 Points
1) Check if the primary and secondary coil is open or
shorted.
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. 10MW, 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.
18
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.