Troubleshooting
Troubleshooting
Microwave Drop-down Door Series
Microwave Drop-down Door Series
4-5
#826151 - Revision A - March, 2016
Perform 3E Checks (page 4-2)1
Remove wires from magnetron2
Test for continuity between magnetron filament terminals. Measurement3
should be less than 1 ohm.
Test for a short circuit, by measuring the resistance between either filament4
terminal and the magnetron case. Measurement should be infinite resist-
ance.
Perform 3E Checks (page 4-2)1
Disconnect the wires from the primary windings of the power transformer2
Disconnect the filament and secondary windings wires from the High3
Voltage (HV) circuitry
Measure the resistance on each of the transformer windings4
a. Primary winding ≈ 0.4 ohms
b. Secondary winding ≈ 123 ohms
c. Filament winding ≈ less than 1 ohm
Perform 4R Checks (4-2)5
Perform 3E Checks (page 4-2)1
Isolate the HV rectifier assembly from the HV circuit2
Measure the resistance between terminals B and C on the HV rectifier -3
note the reading
Reverse the meter leads and measure the resistance between terminals B4
and C again - note the reading
The resistance should be infinite in one direction, and greater than 1005
kOhms in the other direction
Perform 4R Checks (4-2)6
Perform 3E Checks (page 4-2)1
Isolate the HV rectifier assembly from the HV circuit2
Measure the resistance between terminals A and B on the asymmetric recti-3
fier - note the reading
Reverse the meter leads and measure the resistance between terminals A4
and B again - note the reading
If the resistance is infinite in both directions the asymmetric rectifier is good.5
When the asymmetric rectifier is defective, check the magnetron, HV rectifi-6
er, HV wire and filament winding on the power transformer for a short.
Perform 4R Checks (4-2)7
TEST
PROCEDURE
COMPONENT TEST
MAGNETRON TEST
POWER TRANSFORMER
TEST
HIGH VOLTAGE RECTIFIER
ASSEMBLY TEST
ASYMMETRIC RECTIFIER
TEST
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