Read Panasonic NN-E205WB / NN-E235MB / NN-E205WB / NN-E235MB / NN-E205WB / NN-E235MB Service Manual online
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)
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.
WHEN MICROWAVE POWER LEVEL
AND COOKING TIME SET
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”)
(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.
the solid line.
•Turntable rotates.
• The fan motor rotates and cools the magnetron by
• The fan motor rotates and cools the magnetron by
blowing the air (coming from the intake holes on the
baseplate)over the magnetron.
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.
• 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 THE DOOR IS OPENED DURING
COOKING
COOKING
• Both primary switch and secondary switch open to cut
off the primary winding voltage to the high voltage
transformer to stop microwave oscillation.
transformer to stop microwave oscillation.
• Timer, turntable and fan motor stop.
• As the door is opened, if the contact of primary switch
• As the door is opened, if the contact of primary switch
and secondary 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.
to the large current surge caused by the monitor switch
activation which in turn stops magnetron, oscillation.
4-4
FUSE
PRIMARY
SWITCH
SECONDARY
SWITCH
MONITOR
SWITCH
MONITOR
RESISTOR
RESISTOR
L
N
H.V.T
RELAY
TIMER
SWITCH
POWER
CONTROL
SWITCH
FUSE
SECONDARY
SWITCH
MONITOR
SWITCH
MONITOR
RESISTOR
RESISTOR
L
N
H.V.T
RELAY
PRIMARY
SWITCH
TIMER
SWITCH
POWER
CONTROL
SWITCH
Click on the first or last page to see other NN-E205WB / NN-E235MB / NN-E205WB / NN-E235MB / NN-E205WB / NN-E235MB service manuals if exist.