Operation - Viking DMOR206SS Service Manual

The following is a description of component functions dur-
ing 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".
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 shown on page
29.
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, secondary switch and third
door switch and primary 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
of the secondary and third door door switch and primary
interlock relay and 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 primary interlock relay, door sensing switch,
secondary and third door 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 secondary and third door switch close.
If the primaryswitch, secondary switch and secondary in-
terlock relay fail with their contacts closed when the door is

OPERATION

DESCRIPTION OF OPERATING SEQUENCE
opened, the closing of the monitor switch contacts will form
a short circuit through the monitor fuse, secondary switch
,third door switch and primary interlock relay, causing the
monitor 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
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.
CONVECTION COOKING CONDITION
PREHEATING CONDITION
Program desired convection temperature by touching the
PREHEAT pad and the temperature pad.
When the START pad is touched, the following operations
occur:
11
ON TIME OFF TIME
32 sec.
30 sec.
26 sec.
24 sec.
22 sec.
18 sec.
16 sec.
12 sec.
8 sec.
6 sec.
0 sec.
DMOR206SS
0 sec.
2 sec.
6 sec.
8 sec.
10 sec.
14 sec.
16 sec.
20 sec.
24 sec.
26 sec.
32 sec.