Control Board Diagnosis; Line Break Relay; Bake Element - Viking RDSCD230-5B Service Manual

Troubleshooting
To avoid risk of electrical shock, personal injury, or death, disconnect electrical power source to unit, unless test
procedures require power to be connected. Discharge capacitor through a resistor before attempting to service.
Ensure all ground wires are connected before certifying unit as repaired and/or operational.

Control Board Diagnosis

With the control board assembly accessed (see page
22), the following components can be diagnosed without
removal of the components.

Line Break Relay

The line break relay breaks the L2-side of line voltage.
As the relay is energized, the relay closes and allows
L2 power to the convection, broil, and bake elements.
Locate the line break relay on the control board. The
relay will have a red wire and a yellow wire connected to
it. The red wire is L2 input from the main power supply.
The yellow wire is L2 output from the line break relay.
When heating is selected by the control input, voltage is
sent to the line break relay coil. A red LED in front of the
coil verifies coil voltage is being sent to the relay. This
does not indicate however that the relay is functioning.
To check the relay contacts, verify input voltage to the
relay between the red wire (L2) and black wire (L1) at
the connector P12. You should read 240 VAC.
Select a cooking program. When the relay contact is
closed (red LED lit at base of relay) check for 240 VAC
between the yellow wire and black (L1). If 0 VAC is read,
disconnect power and remove the red and yellow wires
off the relay.
Note: Make sure the red and yellow wires that were
removed are not touching anything else prior to
reapplying power.
Reconnect power and using your ohmeter to check for
continuity between the two relay contacts when the relay
is energized. If you read infinite ohms (∞), this indicates
a faulty relay and you will need to replace the control
board.
10

Bake Element

Locate the P5 connector and the line break relay on the
control board. The P5 connector will have a Molex plug
containing a blue, black, and orange wire. The blue wire
goes to the outer bake element, the orange wire goes
to the inner bake element, and the black wire is L1 input
from the main power supply.
With the power off and the Molex connector removed
from the P5 control board connection, use an ohmeter
to measure resistance between the blue wire in the
P5 Molex plug and the yellow wire from the line break
relay. This will measure the resistance of the outer
bake element and should be approximately 38 ohms.
Likewise, the inner bake element can be measured by
reading resistance between the orange wire in the Molex
plug and the yellow wire from the line break relay. A
resistance reading of approximately 38 ohms should be
found. If either element fails to read resistance, remove
element to repair or replace (Follow the bake element
disassembly procedure).
©2012 Viking Preferred Service