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© 2009 Viking Preferred Service
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Selector Switch
DSI Module
Selector Switch
The selector switch controls the cooking operation.
When the end user selects a cooking operation,
the corresponding contacts within the selector
switch close supplying L1 to DSI module, cycle
light, or convection fan motor. Switch contacts BA
to 2, BR to 1, and CV to 3 close for bake, broil, and
convection functions respectfully.
To access the selector switch, slide the unit out 6
to 8 inches. Remove oven selector and thermostat
knobs, remove screws securing thermostat and
selector bezel unscrew bezel for oven light switch,
remove clock buttons, clock knob, remove screws
securing upper trim piece, screws securing control
panel (two at top and bottom and two on each
side). With the aid of a flat blade screwdriver,
separate the control panel from the inner control
panel. Remove two screws securing selector switch
to inner control panel.
Note:
Open oven door, and place oven rack in
highest position, and slide rack out. This will serve
as a support for the control panel during testing
and prevent wires from pulling loose.
The selector switch receives L1 from the thermostat
P7 Red. Closed contacts BA to 2 supplies L1 power
to DSI module position 6 for bake. Closed contacts
BR to 1 supplies L1 power to DSI module position 7
for broil. Closed contacts CV to 3 supplies L1 power
to convection fan motor.
DSI Module
The DSI (Direct Spark Ignition) module provides
spark ignition for the oven burners. When the oven
receives an input from the end user, the selector
switch will send a signal to the DSI module for the
appropriate action. Supply voltage, ground, and
polarity is critical for proper operation of the DSI
module. If voltage is below 100 VAC the flame will
not be reliable. If the voltage is above 130 VAC
damage to the DSI Module can occur. If polarity is
reversed, the DSI Module will not be able to detect
the presence of a flame. Reversed polarity will also
prevent the bake and broil burner from staying lit.
The DSI Module generates a significant amount of
line noise. This line noise is minimized by clamping
it to ground. The absence of a ground can lead to
the line noise resetting the cooking operation. The
module receives the 120 VAC signal and two things
occur. First, the 120 VAC is used to spark the oven
igniters. Second, through rectification the 120 VAC
is stepped down to between 8 and 18 volts DC.
This voltage is sufficient to open the gas valve and
provide gas flow to the appropriate oven burner.
As the gas flow comes in contact with the sparking
igniter ignition occurs. A monitoring system will
look to ensure a flame is present. If a flame is not
present, the igniter will spark for four seconds. If a
flame is still not present, the igniter will be delayed
to allow the cavity to clear of gas. Once the gas
has had time to clear, the igniter will be allowed to
spark again. This process will continue until a flame
is present. If the oven fails to ignite after three tries,
Service Diagnostics and Procedures
