Unsatisfactory Cooking - Samsung M735 Service Manual

6-2 Unsatisfactory Cooking

Parts Cause
1) Open cathode
of magnetron
2) Defective
- H. V. Diode
3) Shorted
magnetron
Food is 4) Defective
not heated. magnetron
5) Poor contact
of primay
interlock switch
6) Open coil of
H. V. Trans-
former
7) Shorted H. V.
capacitor
8) Monitor fuse
blown out
6-3 Part Check List
Symptom Related Parts
Microwave H.V.Transformer
cooking does
not work.
H.V.Capacitor
H.V.Diode
Fan motor Fan motor
does not rotate.
Samsung Electronics
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 megger. 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 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)
Check Points
1) Check if the primary and secondary coil is open or shorted.
* Resistance of primary coil: Approx. 2.30 W
Resistance of secondary coil: Approx. 123W
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.
Troubleshooting
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.
6-3