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Troubleshooting
PROCEDURE
LETTER
4.
Subtract the cold water temperature from the hot water temperature. The normal result should be
28° to 54°F (16° to 30°C) rise in temperature. If the water temperatures are accurately measured
and tested for the required time period the test results will indicate if the magnetron tube has low
power output (low rise in water temperature) which would extend cooking time or high power out-
put (high rise in water temperature) which would reduce cooking time. Because cooking time can
be adjusted to compensate for power output, the magnetron tube assembly should be replaced
only if the water temperature rise test indicates a power output well beyond the normal limits. The
test is only accurate if the power supply line voltage is 120 volts and the oven cavity is clean.
H
THERMAL CUT-OUT TEST
1.
Disconnect the power supply cord.
2.
Open the drawer and keep it open.
3.
To discharge high voltage capacitor, wait for 60 seconds.
4.
A continuity check across the thermal cut-out terminals should indicate a closed circuit unless
the temperature of the thermal cut-out reaches approximately 293°F(145°C). An open thermal
cut-out indicates overheating of the oven, exchange the oven thermal cut-out and check inside of
oven cavity and for improper setting of cooking time or operation of control unit. Check for restrict-
ed air À ow through the vent holes of the oven cavity, especially the cooling fan and air guide.
5.
Reconnect all leads removed from components during testing.
6.
Reassemble the unit.
7.
Reconnect the power supply cord.
8.
Run the unit and check all functions.
CAUTION:
REPLACE THERMAL CUT-OUT.
I
SECONDARY INTERLOCK SWITCH TEST
1.
Disconnect the power supply cord.
2.
Open the drawer and keep it open.
3.
To discharge high voltage capacitor, wait for 60 seconds.
4.
Isolate the switch and connect the ohmmeter to the common (COM.) and normally open (NO) ter-
minal of the switch. The meter should indicate an open circuit with the drawer open and a closed
circuit with the drawer closed. If improper operation is indicated, replace the secondary interlock
switch.
5.
Reconnect all leads removed from components during testing.
6.
Reassemble the unit.
7.
Reconnect the power supply cord.
8.
Run the oven and check all functions.
J
STOP SWITCH TEST
1.
Disconnect the power supply cord.
2.
Open the drawer and keep it open.
3.
To discharge high voltage capacitor, wait for 60 seconds.
4.
Isolate the switch and connect the ohmmeter to the common (COM.) and normally open (NO) ter-
minal of the switch. The meter should indicate an open circuit with the drawer open and a closed
circuit with the drawer closed. If improper operation is indicated, replace the stop switch.
5.
Reconnect all leads removed from components during testing.
6.
Reassemble the unit.
7.
Reconnect the power supply cord.
8.
Run the oven and check all functions.
NOTE: If the stop switch contacts fail in the open position and the door is closed, the cooling fan mo-
tor, stirrer motor and oven light will be activated by RY1.
K
MONITOR SWITCH TEST
1.
Disconnect the power supply cord.
2.
Open the drawer and keep it open.
Drawer Microwave
TEST PROCEDURES
IF THE THERMAL CUT-OUT INDICATES AN OPEN CIRCUIT AT ROOM TEMPERATURE,
COMPONENT TEST
6-10
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