KitchenAid KOMS155MBL Technical Education page 55

TESTING THE AH SENSOR
AND/OR CONTROL UNIT
NOTE: To determine if the sensor is defective,
the simplest method is to replace it with a new
replacement sensor.
1. Disconnect the power supply cord.
2. Remove the cabinet (see page 4-2).
3. Open the door and block it open.
4. To discharge the high voltage capacitor,
wait for 60 seconds.
5. Remove the AH sensor.
6. Install the new AH sensor.
7. Reconnect all leads removed from compo-
nents during testing.
8. Reinstall the cabinet.
9. Reconnect the power supply cord.
10. Reconnect the oven to the power supply
and check the sensor cook operation as
follows:
a) Fill approximately 200 milliliters (7.2 oz)
of tap water in a 1000 milliliter measur-
ing cup.
b) Place the container on the center of tray
in the oven cavity, and close the door.
c) Touch the TIMER/CLOCK keypad once,
the POWER LEVEL keypad twice, the
START pad once, the number pad 1
once, and the number pad 4 once.
d) The control panel is in the "Automatic
Sensor" mode.
e) The oven should turn off automatically,
and the time for detecting moisture
should be displayed.
If the new sensor does not operate properly,
the problem is with the control unit (refer to the
following section).
CHECKING THE CONTROL UNIT
1. Disconnect the power supply cord.
2. Remove the cabinet (see page 4-2).
3. Open the door and block it open.
4. To discharge the high voltage capacitor,
wait for 60 seconds.
5. Disconnect the sensor connector from the
control panel.
6. Connect the dummy resistor circuit (see the
illustration on the next page) to the sensor
connector of the control panel.
7. Disconnect the leads to the primary of the
power transformer. Ensure that these leads
remain isolated from other components and
oven chassis by taping them using insula-
tion tape.
8. Reinstall the cabinet and reconnect the
power supply cord.
9. Check the sensor cook operation as fol-
lows:
a) Touch the TIMER/CLOCK keypad once,
the POWER LEVEL keypad twice, the
START keypad once, the number 1 key-
pad once, and the number 4 keypad
once.
b) The control panel is in the "Sensor
Cooking" mode.
c) After approximately 19 seconds, push
the plunger of the select switch for more
than 3 seconds. This condition is same
as for the AH sensor.
d) After approximately 3 seconds, the dis-
play shows "X X . X X" (the time for de-
tecting moisture). If the display is incor-
rect, the control unit is probably defec-
tive. If the display is correct, the AH sen-
sor is probably defective.
Continued on the next page.
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