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

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Troubleshooting
3-15
Procedure
Letter Component Test
9) Reconnect the oven to the power supply and check the sensor cook operation as follows:
a) Fill approximately 200 milliliters of tap water in a 1000 milliliter measuring cup.
b) Place the container on the center of tray in the oven cavity.
c) Close the door.
d) Touch the SET/CLOCK pad once, the POWER LEVEL pad twice and the START pad
once. And touch the number pads 1 once and the number pad 2 once.
e) The control panel is in automatic Sensor operation.
f) The oven turns off automatically, and the time for detecting moisture will be displayed.
If new sensor dose not operate properly, the problem is with the control unit, and refer to
explanation below.
2. CHECKING CONTROL UNIT
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) Disconnect the sensor connector that is mounted to control panel.
5) Then connect dummy resistor circuit (see fig.) to the sensor connector of control panel.
6) Disconnect the leads to the primary of the power transformer.
7) Ensure that these leads remain isolated from other components and oven chassis by using
insulation tape.
8)
After that procedure, re-connect the power supply cord.
9) Check the sensor cook operation proceed as follows:
a)Close the door. Touch the SET/CLOCK pad once, the POWER LEVEL pad twice and the
START pad once. And touch the number pads 1 once and the number pad 2 once.
b) The control panel is in the sensor cooking operation.
c) After approximately 41 seconds, push plunger of select switch for more than 3 seconds.
This condition is same as judgement by humidity sensor.
d) After approximately 3 seconds, the display shows “X X. X X “ which is the time for
detecting moisture.
If the above is not the case, the control unit is probably defective.
If the above is proper, the humidity sensor is probably defective.
10) Disconnect the power supply cord, and then remove outer case.
11) Open the door and block it open.
12) Discharge high voltage capacitor.
13) Disconnect the dummy resistor circuit from the sensor connector of control panel.
14) Carry out necessary repair.
15) Reconnect all leads removed from components during testing and repairing.
16) Re-install the outer case (cabinet).
17) Reconnect the power supply cord after the outer case is installed. Run the oven and
check all functions.
18) Carry out “Water load cooking test” again and ensure that the oven works properly.
R1,R2:22Ω±1% 1/2W
R3:4.3kΩ±?5% 1/4W
R4:1MΩ±5% 1/4W
Sensor Dummy Resistor Circuit
Plunger
NC
NO
COM
COM
NO
NC
R3 R4
R1
R2
1
2
3
F-1
F-2
F-3
To connector (F)
on Control Unit.
CONNECTOR