9
R-763 -
FUSE F1 F8A 250V
This fuse blows when monitored latch switch
SW1 remains
closed with the oven door open and when the contacts
(
COM + NC) of monitor switch SW2 closes.
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 blows when the asymmetric rectifier, H.V.
rectifier, H.V. wire harness, H.V. capacitor, magnetron or
secondary winding of power transformer is shorted.
SPECIAL FUSE
F2 15A
If the wire harness or electrical components are short-
circuited, this fuse blows to prevent an electric shock or fire
hazard.
THERMAL CUT-OUT 125
°C TC1 (MG)
The thermal cut-out protects the magnetron against
overheat. If this temperature goes up higher than 125°C
because the fan motor is interrupted, the ventilation openings
are blocked, the thermal cut-out
TC1 will open and line
voltages to the power transformer
T will be cut off and the
operation of the magnetron
MG will be stopped. The defective
thermal cut-out
TC1 must be replaced with new one.
THERMAL CUT-OUT 160
°C TC2 (OVEN)
The thermal cut-out located on the top the oven cavity is
designed to prevent damage to the oven if the foods in the
oven catch fire due to over heating produced by improper
setting of cook time or failure of control unit. Under normal
operation, the oven thermal cut-out remains closed.
However, when abnormally high temperatures are reached
within the oven cavity, the oven thermal cut-out will open at
160°C, causing the oven to shut down. The defective
thermal cut-out
TC2 must be replaced with new one.
TURNTABLE MOTOR
The turntable motor drives the turntable roller assembly to
rotate the turntable.
FAN MOTOR
The fan motor drives a blade which draws external cool air.
This cool air is directed through the air vanes surrounding
the magnetron and cools the magnetron. This air is
channeled through the oven cavity to remove steam and
vapours given off from the heating foods. It is then exhausted
through the exhausting air vents at the oven cavity.
NOISE FILTER
The noise filter prevents the radio frequency interference
that might flow back in the power circuit.
GRILL HEATING ELEMENT GH
The grill heating element
GH is located on the top of the
oven cavity assembly. The grill heating element sends out
heat to grill foods.
ASYMMETRIC RECTIFIER
The asymmetric rectifier is a solid state device that prevents
current flow in both directions. And it prevents the tempera-
ture rise of the power transformer by blowing the fuse
F1
when the high voltage rectifier is shorted.
D2 D1
ASYMMETRIC
RECTIFIER
HIGH VOLTAGE RECTIFIER
A
B
C
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 blowing the fuse
F1)
1. The high voltage rectifier is shorted by any causes when
microwave 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.
4. The large electric currents flow through the high voltage
winding of the power transformer.
5. The large electric currents beyond 10A flow through the
primary winding of the power transformer.
6. The fuse
F1 blows by the large electric currents.
7. The power supply to the power transformer is cut off.
FUNCTION OF IMPORTANT COMPONENTS
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