Tech Sheet

FOR SERVICE TECHNICIAN’S USE ONLY
4
TROUBLESHOOTING
Do not continue with the diagnostics of appliance if the household fuse
is blown, a circuit breaker is tripped, or if there is less than 120-volt
power supply at the wall outlet.
Complete the following steps before checking microwave oven circuitry:
1. Unplug microwave oven or disconnect power.
2. Discharge high-voltage capacitor and disconnect white wire from
power transformer.
3. Check for loose wiring or incorrect wiring within microwave oven.
4. All testing must be done with an ohmmeter having a sensitivity of
20,000 ohms per volt DC or greater, and powered by at least a 9-volt
battery.
5. All operational checks using microwave energy must be done with
the microwave oven loaded with a minimum of 8 oz (250 mL) of
water in a microwave safe container.
COMPONENT TESTS
MICROWAVE OVEN POWER OUTPUT TEST
1. Place 8 oz (250 mL) of lukewarm water in the center of the microwave
oven.
2. Operate on HIGH power level for 2 minutes. Water should be hot.
NOTE: If the water takes longer than 2 minutes to heat, this may indicate
either the operating voltage is lower than 110 volts or there is a problem
with the microwave oven.
IMPORTANT
■ Unplug microwave oven or disconnect power.
■ Discharge the high-voltage capacitor and remove the lead wires
from the primary winding of the high-voltage transformer before
conducting any of the following tests.
■ Remove the lead wires from the related component before
conducting any of the following tests.
■ Conduct a microwave energy test after performing any tests or
repairs to the microwave oven.
■ Check that all wire leads are in the correct positions before
operating the microwave oven.
■ All operational checks using microwave energy must be done with
the microwave oven loaded with a minimum of 8 oz (250 mL) of
water in a microwave safe container.
■ Grasp wire connectors when removing the wire leads from
microwave oven parts.
■ All testing must be done with an ohmmeter having a sensitivity
of 20,000 ohms per volt DC or greater, and powered by at least a
9-volt battery.