Viking VHSO205SS Service Manual page 19

PROCEDURE
LETTER
F PRIMARY INTERLOCK SYSTEM TEST
DOOR SENSING SWITCH
1. Disconnect the power supply cord, and then remove outer case.
. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Isolate the switch and connect the ohmmeter to the common (COM.) and normally open (NO) terminal
of the switch. The meter should indicate an open circuit with the door open and a closed circuit with the
door closed. If improper operation is indicated, replace the door sensing switch.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
NOTE: If the door sensing switch contacts fail in the open position and the door is closed, the turntable
motor and oven light will be activated by RY1.
PRIMARY INTERLOCK RELAY (RY)
1. Disconnect the power supply cord, and then remove outer case.
. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect two () wire leads from the male tab terminals of the Primary Interlock Relay (RY). Check
the state of the relay contacts using a ohmmeter. The relay contacts should be open. If the relay contacts
are closed, replace the circuit board entirely or the relay itself.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
G MONITOR SWITCH
1. Disconnect the power supply cord, and then remove outer case.
. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Before performing this test, make sure that the secondary interlock switch and the primary interlock relay
are operating properly, according to the above Switch Test Procedure. Disconnect the wire lead from the
monitor switch (COM) terminal. Check the monitor switch operation by using the ohmmeter as follows.
When the door is open, the meter should indicate a closed circuit. When the monitor switch actuator is
pushed by a screw driver through the lower latch hole on the front plate of the oven cavity with the door
opened (in this condition the plunger of the monitor switch is pushed in), the meter should indicate an
open circuit. If improper operation is indicated,
the switch may be defective. After testing the
monitor switch, reconnect the wire lead to the
monitor switch (COM) terminal and check the
continuity of the monitor circuit.
5. Reconnect all leads removed from components
during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer
case is installed.
8. Run the oven and check all functions.
H BLOWN MONITOR FUSE
1. Disconnect the power supply cord, and then remove outer case.
. Open the door and block it open.
3. Discharge high voltage capacitor.
4. If the monitor fuse is blown when the door is opened, check the primary interlock relay, secondary interlock
switch and monitor switch according to the "TEST PROCEDURE" for those switches before replacing
the blown monitor fuse.
CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE, TEST THE PRIMARY INTERLOCK
TEST PROCEDURES
COMPONENT TEST
Monitor switch
Screw driver
19
GRY
BLK
OHMMETER
Secondary
interlock switch
Latch hook left
VHSO205SS