CIRCUIT DESCRIPTION
� As the door is closed, the contact of MONITOR SWITCH opens. This switch creates the short circuit to blow fuse during operation under abnormal condition. (ie, should the contacts of primary and secondary switch fail to open the circuit) � The latches are secured by latch board. The oven light turns on while the oven is in operation. � 3.2 volts AC is generated from the filament winding of the high voltage transformer. This 3.2 volts is applied to the magnetron to heat the magnetron filament through two noise preventing choke coils. A high voltage of approximately 2100 volts AC is generated in the secondary of the high voltage transformer which is increased by the action of the diode and charging of the high voltage capacitor. The negative DC voltage is then applied to the filament of the magnetron
WHEN MICROWAVE POWER LEVEL AND COOKING TIME SET
� The contacts of the timer switch changes to ON position when the timer knob is rotated. (While power control knob is set at �Full Power�) � The contacts of primary and secondary switch close the circuit. � Input Volts AC. is applied to the high voltage transformer through power control switch as shown by the solid line.
POWER CONTROL SWITCH H.V.T FUSE L N MONITOR SWITCH
WHEN THE DOOR IS OPENED DURING COOKING
� Both primary switch and secondary switch open to cut off the primary winding voltage to the high voltage transformer to stop microwave oscillation. � Timer, turntable and fan motor stop. � As the door is opened, if the contact of primary switch fail to open, the fuse opens due to the large current surge caused by the monitor switch activation which in turn stops magnetron, oscillation.
PRIMARY TIMER SWITCH SWITCH
PRIMARY TIMER SWITCH SWITCH FUSE L N SECONDARY SWITCH
POWER CONTROL SWITCH H.V.T
MONITOR SWITCH
� Turntable rotates. � The fan motor rotates and cools the magnetron by blowing the air (coming from the intake holes on the baseplate) over the magnetron. � The air is also directed into the oven to exhaust the vapor in the oven through the upper plate. � Timer starts rotating.
