High-Voltage Diode; Power Resistor - Whirlpool MH3184XPB Service Manual

Disconnect power before servicing.
Replace all parts and panels before operating.
Failure to do so can result in death or electrical shock.

HIGH-VOLTAGE DIODE

H.V. diode
Refer to page 4-20 for the procedure for ac-
cessing the high-voltage (H.V.) diode.
NOTE: Some inexpensive ohmmeters do not
have a 9-volt battery incorporated in them, and
may indicate infinite resistance in both directions
when testing the diode. It is recommended that
you use an ohmmeter with a 9-volt battery on
the R x 10 scale to properly test the H.V. diode.
1. Unplug microwave oven or disconnect
power.
2. Discharge the high-voltage capacitor by
touching the leads of a 20,000 Ω resistor
from each of the capacitor leads to chas-
sis ground.
3. Disconnect the H.V. diode lead from the
high voltage capacitor terminal.
4. For ohmmeters without a 9-volt battery,
prepare the DC 9-volt battery and 10 kΩ
resistor in series including wire leads.
5. Connect the DC 9-volt battery to the H.V.
diode.
6. Set the ohmmeter to the R x 10K scale.
7. Measure the continuity as follows (values
are approximate):
• Forward Direction: Normal: 5 to 6 volts.
Abnormal: Open = 9 volts, short = 0
volts.
• Reverse Direction: Normal: 9 volts.
Abnormal: Open = 9 volts, short = 0 volts.
WARNING
Electrical Shock Hazard

POWER RESISTOR

Refer to page 4-20 for the procedure for ac-
cessing the power resistor.
1. Unplug microwave oven or disconnect
power.
2. Disconnect one of the wires from the
power resistor terminals.
3. Set the ohmmeter to the R x 1 scale.
4. Touch the ohmmeter test leads to the
filament terminals. The meter should in-
dicate between 37 and 45 Ω.
5-6