Wolf MWD24-2 Service Manual page 58

Troubleshooting Guide
PROCEDURE LETTER
F
(Cont.)
#813632 - Revision B - December, 2009
Drawer Microwave
TESTING METHOD FOR AH SENSOR AND/OR CONTROL UNIT:
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, and then disassemble as per "Drawer
Microwave Disassembly" Section 4 Component Access Removal, Page 4-6.
2. Open the drawer and block it open.
3. Discharge high voltage capacitor.
4. Remove the AH sensor.
5. Install the new AH sensor.
6. Reconnect all leads removed from components during testing.
7. Re-install the covers.
8. Reconnect the power supply cord after the covers are installed.
9. Reconnect the oven to the power supply and check the sensor cook operation
as follows:
• Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter
measuring cup.
• Place the container on the center of tray in the oven cavity.
• Close the drawer.
• Touch the TIMER/CLOCK pad once, the POWER LEVEL pad twice and
the START pad once. And touch the number pads 1 once and the num-
ber pad 4 once.
• The control panel is in automatic Sensor operation.
• The oven turns off automatically, and the time for detecting moisture will
be displayed.
If new sensor does not operate properly, the problem is with the control unit, and
refer to explanation be-low.
CHECKING CONTROL UNIT:
1. Disconnect the power supply cord, and then disassemble as per "Drawer
Microwave Disassembly" Section 4 Component Access Removal, Page 4-6.
2. Open the drawer and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the sensor connector that is mounted to control panel.
5. Then connect the 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:
• Close the door. Touch the TIMER/CLOCK pad once, the POWER LEVEL
pad twice and the START pad once. And touch the number pads 1 once
and the number pad 4 once.
• The control panel is in the sensor cooking operation.
• After approximately 25 seconds, push plunger of select switch for more
than 3 seconds. This condition is same as judgement by AH sensor.
• 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 AH sensor is proba-
bly defective. If the above is proper, the AH sensor is probably defective.
5-10
(Models MWD24-2 / MWD30-2)
COMPONENT TEST
(This Section continues on the next page)