Testing Control Board; Testing The Capacitors; Testing Fan Motor - Viking RDSCD230-5B Service Manual

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.

Testing Control Board

Leave the Molex connector attached to P4 board
connection. While the convection fan is turning in
the forward direction (clockwise), use a voltmeter to
measure voltage between the blue/black wire in the
Molex plug and the red wire (L2) at the line break relay.
The voltage should be 240 VAC. This will indicate the
K5 and K6 of the oven control board are functioning
properly.
Leave the Molex connector attached to P4 board
connection. While the convection fan is turning in the
reverse direction (counterclockwise), use a voltmeter
to measure voltage between the orange/black wire in
the Molex plug and the red wire (L2) at the line break
relay. The voltage should be 240 VAC. This will indicate
the K5 and K6 of the oven control board are functioning
properly.
When K7 is at rest, testing between LO and L2 should
show a voltage reading of 240 VAC. The red LED in front
of the relay will NOT be lit. When K7 is energized, testing
between HI and L2 should show a voltage reading of
240 VAC and the red LED in front of the relay will be
illuminated.
If voltage is not present, this indicates a faulty relay
and the oven control board will need to be replaced.
Also check wiring to the main power supply and repair/
replace as needed.
©2012 Viking Preferred Service

Testing The Capacitors

The range uses two 2mF capacitors. Using either an
analog or digital meter, use your highest ohms setting
and check between each terminal of the capacitor. Make
sure one of the leads to the capacitor is temporally
removed. On an analog meter, the pointer will increase
until it reaches its capacitance (nearly infinity), then
return to 0 ohms. Reversing the leads will repeat the
process. On a digital multimeter, the pointer is replaced
by the value displayed by a numerical number in the
display. It too will return to 0 ohms indicating a good
capacitor.
If the capacitor(s) is open, then it will never charge. If it
is shorted, the resistance will be infinite immediately and
won't change. If either is true, replace the capacitor(s).

Testing Fan Motor

If all the voltage tests on the oven control board are
correct, the capacitors and the convection motor need
to be checked. With the Molex connector removed from
the P4 board connection and capacitor leads removed,
use an ohmeter to measure resistance between blue/
black wire (forward direction) in the Molex plug and the
red wire at the line break relay. The resistance should be
approximately 100 ohms. Likewise, the reverse direction
can be measured by reading resistance between the
yellow/white wire in the Molex plug and the red wire at
the line break relay. Resistance should be approximately
100 ohms. If either or both readings are not as shown,
replace the convection fan motor (Follow the convection
fan disassembly procedure).
Troubleshooting
15