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Variable Cooking
When Variable Cooking Power is programmed, the 120
volts A.C. is supplied to the power transformer intermit-
tently through the contacts of relay (RY-2) which is
operated by the control unit within a 32 second time
base. Microwave power operation is as follows:
Vari-Mode
Power 10 (High) (100% Power)
Power 9 (P-90) (Approx. 90%)
Power 8 (P-80) (Approx. 80%)
Power 7 (P-70) (Approx. 70%)
Power 6 (P-60) (Approx. 60%)
Power 5 (P-50) (Approx. 50%)
Power 4 (P-40) (Approx. 40%)
Power 3 (P-30) (Approx. 30%)
Power 2 (P-20) (Approx. 20%)
Power 1 (P-10) (Approx. 10%)
Power 0 (P-0) (0% power)
The ON/OFF time ratio does not correspond with the
percentage of microwave power, because approx. 2
seconds are needed for heating of the magnetron
filament.
Component Descriptions
DOOR OPEN MECHANISM
The door is opened by pulling the door handle down and
forward, referring to Figure 2-6. When the door handle is
pulled down, the latch heads are moved upward. When
the door handle is pulled forward, the latch heads are
released from the latch hooks right and left. Now, the
door will open.
Figure 2-6.
ON TIME
OFF TIME
32 sec.
0 sec.
30 sec.
2 sec.
26 sec.
6 sec.
24 sec.
8 sec.
22 sec.
10 sec.
18 sec.
14 sec.
16 sec.
16 sec.
12 sec.
20 sec.
8 sec.
24 sec.
6 sec.
26 sec.
0 sec.
32 sec.
PRIMARY SWITCH, THIRD DOOR SWITCH & DOOR
SENSING SWITCH
The primary switch and third door switch mounted
parallel to each other horizontally in the lower positions of
the latch hook, and the door sensing switch is mounted
horizontally in the upper position of the latch hook. They
are activated by the latch head on the door. When the
door is opened, the switches interrupt the power to all
high voltage components, except the oven lamp. A cook
cycle cannot take place until the door is firmly closed,
thereby activating all interlock switches. The secondary
interlock system consists of the door sensing switch
and the secondary interlock relay, located on the control
circuit board.
MONITOR SWITCH
The monitor switch is activated (the contacts opened)
by the latch head on the door while the door is closed.
The switch is intended to render the oven inoperative,
by means of blowing the C/T fuse, when the contacts of
the secondary interlock relay (RY2) and primary interlock
switch fail to open when the door is opened.
Functions:
1. When the door is opened, the monitor switch contact
closes (to the ON condition) due to their being
normally closed. At this time the secondary interlock
relay, primary switch and third door switch are in the
OFF condition (contacts open) due to their being
normally open contact switches.
2. As the door goes to a closed position, the monitor
switch contacts are first opened and then the door
sensing switch, primary switch and third door switch
contacts close. (On opening the door, each of these
switches operate inversely.)
3. If the door is opened, and the secondary interlock
relay (RY2) and primary interlock switch contacts fail
to open, the C/T fuse blows simultaneously with
closing of the monitor switch contacts.
Before replacing a blown C/T fuse, test the door
sensing switch, secondary interlock relay (RY2),
relay (RY1), primary/third door interlock switch and
monitor switch for proper operation.
Monitor fuse and switch are replaced as an assembly.
2-3
Operation
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