Sharp R-1880LS Service Manual page 24

R-1880LS/LST
PROCEDURE
LETTER
PRIMARY INTERLOCK RELAY (RY)
F
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. 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 TEST
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 primary interlock switch and the secondary interlock relay are
operating properly, according to the above Switch Test Procedure. Disconnect the wire lead from the monitor
switch (NC) 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 (NC) 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 DAMPER SWITCH TEST
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 the wire leads from the switch terminals and connect ohmmeter leads to the
common (COM.) and normally open (N.O.) terminals of the switch.
5. When switch actuator is pushed by the damper cam, the meter should be indicated a closed circuit.
6. When power cord is plugged into the wall receptacle, the damper motor operates and damper cam will start
to rotate. When the switch actuator is released, the meter should be indicated an open circuit. If improper
operation is indicated, replace the damper switch.
7. Reconnect all leads removed from components during testing.
8. Reinstall the outer case (cabinet).
9. Reconnect the power supply cord after the outer case is installed.
10. Run the oven and check all
functions.
TEST PROCEDURES
COMPONENT TEST
SCREW
DRIVER
4
WHITE
BLACK
BLACK
MONITOR SWITCH