Sharp R-CD1200M Service Manual page 12

RCD1200M
During cooking, they operate. After cooking, they will operate at least
for 1 minute and the maximum operating time is 4 minutes. When the
temperature of the magnetron thermistor becomes bellow 110°C, the
fan motors will stop. These two (2) fan motors are D.C. motors.
11. EXHAUST MOTOR
The exhaust motor is located on the side of the exhaust duct assem-
bly. This motor drives a blade in the exhaust duct assembly. The
driven blade draws the external cool air into the oven from the intake
duct assembly. Then it sends the air out of the oven through the
exhaust duct assembly. During cooking, the exhaust motor operates.
After cooking, it will operate at least for 1 minute and the maximum
operating time is 4 minutes. When the temperature of the exhaust
thermistor becomes bellow 65°C, the exhaust motor will stop. This
motor is D.C. motor.
NOTE: Do not disconnect the power supply from the exhaust motor
when it is turned on. Or it may be out of order.
12. ANTENNA MOTORS
The upper and lower antenna motors drive antennas to radiate the
microwave.
13. EXHAUST FAN
The exhaust fan is located to the rear cover. It sends the air (which is
at the top of the oven cavity) out of the oven. This motor is D.C. motor.
14. ANTENNA SENSOR
The antenna sensors are located to the top and bottom of the oven
cavity. And they watch if the antennas are rotating or not.
15. MIROWAVE SENSOR
The microwave sensor is located on the top of the oven cavity. And it
watch if the microwave is radiated into the oven cavity or not.
16. FUSE 12A (1) (2)
1. If the wire harness or electrical components are short-circuited, this
fuse blows to prevent an electric shock or fire hazard.
2. The fuse also blows when the asymmetric rectifier, H.V. rectifier,
H.V. wire harness, H.V. capacitor, magnetron or secondary winding
of high voltage transformer is shorted.
17. H.V. ASYMMETRIC RECTIFIER (1) (2)
The H.V.asymmetric rectifiers (1) (2) are solid state devices that pre-
vent current flow is both directions. And they prevent the temperature
rise of the high voltage transformers (1) (2) by blowing the fuses 12A
(1) (2) when the high voltage rectifiers (1) (2) are shorted. The rated
peak reverse voltage of D1 of the asymmetric rectifier is 6 KV. The
rated peak reverse voltage of D2 of the asymmetric rectifier is 1.7 KV.
D1 and D2 of the asymmetric rectifier or high voltage rectifier are
shorted when the each peak reverse voltage goes beyond the each
rated peak reverse voltage. (The process of the blowing the fuse 12A.)
D2 D1
ASYMMETRIC
RECTIFIER
NOTE: The H.V.asymmetric rectifier is assembled with the high volt-
age rectifier actually.
1. The high voltage rectifier is shorted by some fault when microwave
cooking or dual cooking.
2. The peak reverse voltage of D2 of the rectifier goes beyond the
rated peak reverse voltage 1.7 KV in the voltage doubler circuit.
3. D2 of the rectifier is shorted.
HIGH VOLTAGE
RECTIFIER
5 – 4
4. The large electric currents flow through the high voltage winding of
the high voltage transformer.
5. The large electric currents beyond 12A flow through the primary
winding of the high voltage transformer.
6. The fuse 12A blows by the large electric currents.
7. The power supplying to the high voltage transformer is cut off.
18. OVEN LAMP
The oven cavity light illuminates the interior of the oven so that food
being cooked can be examined visually through the door window with-
out having to open the door.
19. NOISE FILTER
The noise filter prevents the radio frequency interference that might
flow back in the power circuit.