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TEST PROCEDURES
PROCEDURE
NUMBER
COMPONENT TEST
1
MAGNETRON
ASSEMBLY
TEST
HlGH VOLTAGES ARE PRESENT DURING THE COOK CYCLE, SO EXTREME CAUTION SHOULD BE
OBSERVED.
DISCHARGE THE HIGH VOLTAGE CAPACITOR
BEFORE TOUCHING ANY OVEN COMPONENTS OR
WIRING.
To test for an open filament,
isolate the magnetron from the high voltage circuit. A continuity
check across the
magnetron filament leads should indicate less than 1 ohm.
To test for a shorted magnetron,
connect the ohmmeter leads between the magnetron filament leads and chassis
ground. This test should indicate an infinite resistance.
If there is little or no resistance, the magnetron is grounded and must be replaced.
Power output of the magnetron can be measured by means of a water temperature rise test. This test should only be
used if the preceding test does not indicate a faulty magnetron and there is no defect on the following components
or wiring; rectifier, high vcltage capacitor and power transformer.
Refer to Microwave Output Power.Measurement
in GENERAL SERVICE MANUAL on pages 6 and 7.
2
POWER TRANSFORMER
TEST
DISCHARGE
THE HIGH VOLTAGE
CAPACITOR BEFORE TOUCHING ANY OVEN COMPONENTS OR
WIRING.
Disconnect primary input terminais and measure the resistance with an ohmmeter. Check for the continuity
of
coils with an ohmmeter.
On the RX1 scale, the resistance of the primary coil should be approximately
1.5 ohms
and the resistance of high voltage coil should be approximately
105 ohms, and the resistance of filament coil
should be lessthan 1 ohm. With 220/240 volts A.C. applied to the primary winding, the voltage across the filament
tiding
should be approximately
3.15 volts A.C. (HIGH VOLTAGES ARE PRESENT TO HIGH VOLTAGE
TERMINAL, SO EXTREME CAUTION SHOULD BE OBSERVED.)
3
UPPER
LATCH SWITCH TEST
The upper latch switch can be checked with an ohmmeter.
Isolate the switch and then connect the meter
leads to the common (COM) and normally open (NO) terminals of ths switch. The meter should indicate an open
circuit with the door opened and a closed circuit with the door closed.
In case improper operation is indicated, make a necessary switch adjustment or replace the defective switch.
See adjustment procedure on page 31.
4
LOWER LATCH SWITCH TEST
Isolate the switch and connect the ohmmeter leads to the common (COM) and normally open (NO) terminals of the
switch.
The meter should indicate an open circuit with the door opened and a closed circuit with the door closed.
When the meter leads connected to the common (COM) and normally closed (NC) terminals of the switch, it should
indicate a closed circuit with the door opened and an open circuit with the door closed.
In case improper operation is indicated, make a necessary switch adjustment or replace the defective switch.
See adjustment procedure on page 31.
5
VARI-SWITCH
TEST
The vari-switch .is activated by the cam lever and cam. When the Variable cooking control is set at " &:
FULL
POWER" position, the cam is placed far away from the cam lever. In this condition, the vari-switch is turned ON by
action of the cam lever. The vari-switch can be checked with an ohmmeter.
When the meter leads connected
to the common (COM) and normally open (NO) terminals of the switch, it should
indicate a closed circuit with the cam lever depressed and an open circuit with the cam lever released. If improper
operation is indicated, replace the vari-motor assembly.
6
VARI-MOTOR
TEST
The vari-motor rotates two (2) revolutions per minute.
Check if 220/240 volts is present between the motor terminals. If voltage is present,
but the motor does not turn, ,
replace the vari-motor assembly.
If no voltage is present, check for loose or broken wire connections.
22
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