Operation - Electrolux PLMV169DCC Service Manual

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The following is a description of component functions during
oven operation.
OFF CONDITION
Closing the door activates the door sensing switch and
secondary interlock switch. (In this condition, the monitor
switch contacts are opened.)
When oven is plugged in, 120 volts A.C. is supplied to the
control unit. (Figure O-1).
1. The display will show "WELCOME, PRESS CLEAR AND
PRESS CLOCK".
To set any program or set the clock, you must first touch
the STOP/CLEAR pad. The display will clear, and " : "
will appear .
COOKING CONDITION
Program desired cooking time touching the NUMBER pads.
When the START pad is touched, the following operations
occur:
1. The contacts of relays are closed and components
connected to the relays are turned on as follows.
(For details, refer to Figure O-2)
RELAY CONNECTED COMPONENTS
RY1 Oven lamp / Fan motor / Stirrer motor
RY2 Power transformer
RY3 Turntable motor
RY4 Hood fan motor
2. 120 volts A.C. is supplied to the primary winding of the
power transformer and is converted to about 3.3 volts
A.C. output on the filament winding, and approximately
2000 volts A.C. on the high voltage winding.
3. The filament winding voltage heats the magnetron filament
and the H.V. winding voltage is sent to a voltage doubler
circuit.
4. The microwave energy produced by the magnetron is
channelled through the waveguide into the cavity feed-
box, and then into the cavity where the food is placed to
be cooked.
5. Upon completion of the cooking time, the power
transformer, oven lamp, etc. are turned off, and the
generation of microwave energy is stopped. The oven
will revert to the OFF condition.
6. When the door is opened during a cook cycle, monitor
switch, door sensing switch, primary interlock switch, and
secondary interlock relay are activated with the following
results. The circuits to the stirrer motor, the cooling fan
motor, the turntable motor, and the high voltage
components are de-energized, and the digital read-out
displays the time still remaining in the cook cycle when
the door was opened.
7. The monitor switch is electrically monitoring the operation

OPERATION

DESCRIPTION OF OPERATING SEQUENCE
of the primary interlock switch, and door sensing switch
is mechanically associated with the door so that it will
function in the following sequence.
(1) When the door opens from a closed position, the
secondary interlock relay, door sensing switch, and
primary interlock switch open their contacts, and then
the monitor switch contacts close.
(2) When the door is closed from the open position, the
monitor switch contacts first open, and then the
contacts of the primary interlock switch close.
If the primary interlock switch fail with their contacts closed
when the door is opened, the closing of the monitor switch
contacts will form a short circuit through the C/T fuse, primary
interlock switch and causing the C/T fuse to blow.
POWER LEVEL P-0 TO P-90 COOKING
When Variable Cooking Power is programmed, the 120 volts
A.C. is supplied to the power transformer intermittently
through the contacts of relay (RY2) which is operated by the
control unit within an interval second time base. Microwave
power operation is as follows:
VARI-MODE ON TIME
Power 10(P-HI)
(100% power)
Power 9(P-90)
(approx. 90% power)
Power 8(P-80)
(approx. 80% power)
Power 7(P-70)
(approx. 70% power)
Power 6(P-60)
(approx. 60% power)
Power 5(P-50)
(approx. 50% power)
Power 4(P-40)
(approx. 40% power)
Power 3(P-30)
(approx. 30% power)
Power 2(P-20)
(approx. 20% power)
Power 1(P-10)
(approx. 10% power)
Power 0(P-0)
(0% power)
Note: 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.
BREAKFARST, LUNCH, DINNER
BREAKFAST, LUNCH, DINNER will automatically compute
the microwave power and cooking time. Set the desired
7
PLMV169DCC
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.