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.
WARNING
!
With the power off and Molex connector
removed from the P2 control board
connection, use an ohmeter to measure
resistance between the white/red wire in the
Molex plug and the yellow wire at the line
break relay. This will measure the resistance
of the convection element and should be
approximately 18 ohms. If the element fails
to read resistance, remove element to repair/
replace (Follow the convection element
disassembly procedure).
Convection Element (continued)
Convection Relay
When the convection element is selected by
the oven control board, voltage is sent to the
convection relay coils. A red LED in front of
each coil verifies coil voltage is being sent to
that particular relay. This does not indicate
however that the relay is functioning. When
the convection element relay is energized,
(L1-black) power is sent through the relay
to the convection element. (L2 power is
controlled by the line break relay.)
To test, select a cooking program. When the
convection relay contact is energized (red
LED lit at base of relay), check for 240 VAC
between the yellow wire at the line break
relay and the white/red wire on P2. If 0 VAC is
read, disconnect power and remove P2 Molex
plug.
Reconnect power and using your ohmeter,
check for continuity between the two relay
contacts (refer to photo, above). If you read
infinite ohms (∞) when the relay is energized,
this indicates a faulty relay and you will need
to replace the control board. If you read 0
ohms, the relay contact is closing.
Cooling Fan
Locate the P11 terminal connections on the
control board. The P11 connections will have
Molex plug containing two white/black wires.
With the P11 board connection removed, use
an ohmeter to measure resistance between
either white/ black wire and P1 white wire
on the power supply board. The resistance
should be approximately 18 ohms. If no
resistance is read, remove fan to repair/
replace (Follow the cooling fan disassembly
procedure).
With the white/black wires attached to the
P11 board connection, use a voltmeter to
measure voltage between the white/black
wires on the board and P1 white on the
power supply board. The voltage should
be 120 VAC. If 120 VAC is present and no
fan rotation, replace the cooling fan (follow
cooling fan disassembly procedure). If no
voltage is present, verify wiring. If wiring is
OK, replace the oven control board.
Troubleshooting
©2012 Viking Preferred Service
15