Electrolux EI30BM55HB - 30" Microwave Oven, Technical & Service Manual

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Troubleshooting
3-5
Procedure
Letter
B
C
Component Test
POWER TRANSFORMER TEST
WARNING: DO NOT TOUCH THE COMPONENTS OF THE POWER TRANSFORMER
WHILE POWER TRANSFORMER IS ENERGIZED. IT IS DANGEROUS
BECAUSE THIS HAS HIGH VOLTAGE COMPONENTS.
(HIGH VOLTAGES ARE PRESENT AT THE HIGH VOLTAGE TERMINAL, SO DO
NOT ATTEMPT TO MEASURE THE FILAMENT AND HIGH VOLTAGE.)
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. To discharge high voltage capacitor, wait for 60 seconds.
4. Disconnect the primary input terminals and measure the resistance of the transformer with
an ohmmeter. Check for continuity of the coils with an ohmmeter. On the R x 1 scale, the
resistance of the primary coil should be less than 1 ohm and the resistance of the high volt-
age coil should be approximately 85 ohms; the resistance of the filament coil should be less
than 1 ohm.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
HIGH VOLTAGE RECTIFIER TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Isolate the rectifier from the circuit. Using the highest ohm scale of the meter, read the
resistance across the terminals and observe, reverse the leads to the rectifier terminals and
observe meter reading. If a short is indicated in both directions, or if an infinite
resistance is read in both directions, the rectifier is probably defective and should be
replaced.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
NOTE: Be sure to use an ohmmeter that will supply a forward bias voltage of more than 6.3
volts.