Samsung CO88R Service Manual page 19

Circuit Description
6-4 When the door is opened during cooking
1. The primary interlock switch is opened to cut off the primary voltage of the high voltage transformer.
This stops microwave oscillation.
2. The door sensing switch(the primary switch) is opened which signals the touch control circuit. The main
relay stays on, the power control relay turns off and the display stops counting down.
3. The tuen table motor is stopped and the oven lamp is furned off by operation of the primary interlock
switch. The fan motor is stopped by fan motor relay on the touch control circuit.
4. Upon opening the door, the contacts of the primary and secondary interlock switch open and the
contacts of interlock monitor switch close.
5. If the contacts of primary interlock switch do not function properly, the fuse blows out because of the
large current surge (caused by the monitor switch activation, which stops magnetron oscillation). see
Fig. 3
6-5 When the CANCEL pad is touched during cooking
1. Touching the CANCEL pad cancels all programs stored in the touch control circuit. The time of day
reappears on the display window.
2. The oven lamp and cooking indicators turn off.
3. The fan motor stops.
4. The power control relay turns off to cutting the primary voltage to the high voltage transformer (This
stops magnetron oscillation).
6-2
Primary Switch
Monitor
Switch
Secondary
Switch
Fuse
H.V.Trans
Power Relay
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