Page 33
MD24 and MD30
Troubleshooting Guide
5-10
#824820 - Revision A - December, 2013
MICROWAVE OUTPUT POWER:
• THE OVEN SHOULD BE FULLY ASSEMBLED BEFORE ATTEMPTING THE
FOLLOWING PROCEDURE.
• HIGH VOLTAGES ARE PRESENT DURING COOK CYCLE, SO EXTREME CAU-
TION SHOULD BE OBSERVED.
Power output of magnetron can be measured by performing a water temperature
rise test. This test should only be used if above tests do not indicate a faulty
magnetron and there is no defect in following components or wiring: This test will
require a 16 ounce (453cc) measuring cup and an accurate mercury thermometer
or thermocouple type temperature tester. For accurate results, following proce-
dure must be followed carefully:
1. Fill measuring cup with 16 oz. (453cc) of tap water and measure temperature
of water with a thermometer or thermocouple temperature tester. Stir ther-
mometer or thermocouple through water until the temperature stabilizes.
Record temperature of water.
2. Place cup of water in oven. Operate oven at POWER 10(HIGH) selecting
more than 60 seconds cook time. Allow water to heat for 60 seconds, meas-
uring with a stop watch, second hand of a watch or digital read-out count-
down.
3. Remove cup from oven and again measure temperature, making sure to stir
thermometer or thermocouple through water until maximum temperature is
recorded.
4. Subtract cold water temperature from hot water temperature. The normal
result should be 28° to 54°F (16° to 30°C) rise in temperature. If water tem-
peratures are accurately measured and tested for required time period test
results will indicate if magnetron tube has low power output (low rise in water
temperature) which would extend cooking time or high power output (high rise
in water temperature) which would reduce cooking time. Because cooking
time can be adjusted to compensate for power output, magnetron tube
assembly should be replaced only if water temperature rise test indicates a
power output well beyond the normal limits. The test is only accurate if power
supply line voltage is 120 volts and oven cavity is clean.
G
MAGNETRON ASSEMBLY TEST:
1. Disconnect power supply cord.
2. Open drawer and keep it open.
3. To discharge high voltage capacitor, wait for 60 seconds.
4. To test for an open filament, isolate magnetron from high voltage circuit. A
continuity check across magnetron filament leads should indicate less than 1
ohm.
5. To test for a shorted magnetron, connect ohmmeter leads between magnetron
filament leads and chassis ground. This test should indicate an infinite resist-
ance. If there is little or no resistance magnetron is grounded and must be
replaced.
6. Reconnect all leads removed from components during testing.
7. Reassemble unit.
8. Reconnect the power supply cord.
9. Run oven and check all functions.
COMPONENT TEST
PROCEDURE LETTER
