Electrolux ICON E30SO75ESS Technical & Service Manual page 26

Troubleshooting and Testing
Procedure
Letter
B POWER TRANSFORMER TEST
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. Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
4. Remove the back plate from the oven.
5. 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 R x 1 scale, the resistance
of the primary coil should be 1.3 ohms and the resistance of the high voltage coil should be ap-
proximately 75 ohms; the resistance of filament coil should be less than 1 ohm.
6. Also, the power transformer has the thermostat in the primary coil. Measure the resistance of the
primary coil. The resistance of the primary coil should be above resistance unless the tempera-
ture of the thermostat in the primary coil reaches approximately 320°F (160°C). The thermostat
resets automatically at 221°F(105°C). If an ohmmeter indicates an open circuit under normal
condition, replace the power transformer because the primary coil (thermostat) has opened.
An open primary coil (thermostat) indicates overheating of the power transformer. Check for
restricted air flow to the power transformer, especially the fan motor (power transformer side).
7. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet) and back plate.
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
C
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. (See Warnings and Instructions on page 3-1)
4. Remove the back plate from the oven.
5. 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.
6. Reconnect all leads removed from components during testing.
7. Reinstall the outer case (cabinet) and backplate.
8. Reconnect the power supply cord after the outer case is installed.
9. 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.
Component Test
3-4