Page 32
Troubleshooting Guide
MD24 and MD30
5-9
#824820 - Revision A - December, 2013
COMPONENT TEST
PROCEDURE LETTER
F - continued
TESTING METHOD FOR AH SENSOR:
To determine if sensor is defective, the simplest method is to replace it with a new
sensor.
1. Disconnect power supply cord, and then disassemble as per “Drawer
Microwave Disassembly” Section 4 Component Access Removal, starting on
Page 4-4.
2. Open drawer and block it open.
3. Discharge high voltage capacitor.
4. Remove AH sensor.
5. Install the new AH sensor.
6. Reconnect all leads removed from components during testing.
7. Re-install outer case.
8. Reconnect power supply cord after outer case is installed.
9. Reconnect oven to power supply and check sensor cook operation as follows:
•
Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter
measuring cup.
•
Place container on center of tray in oven cavity.
•
Close drawer.
•
Touch the TIMER/CLOCK pad once, POWER LEVEL pad twice and
START pad once. Touch number pad 1 once and number pad 4 once.
•
CPU-Drawer board is in automatic Sensor operation.
•
Oven turns off automatically, and time for detecting moisture will be dis-
played.
If new sensor does not operate properly, problem is most likely with PSU-Drawer
board. Further testing of CPU-Drawer board requires construction of a Dummy
Resistor Circuit.
F1 to F3
3k
Ω
Measuring
Approx ohms @ 77F
F2 to F3
2k
Ω
~ 3k
Ω
F1 to F2
5k
Ω
~ 6k
Ω
S
C
F-2
F-3
F-1
Figure 5-1. AH Sensor Resistance
10. Disconnect power supply cord, and then remove covers.
11. Open the drawer and block it open.
12. Discharge high voltage capacitor.
13. Carry out necessary repair.
14. Reconnect all leads removed from components during testing and repairing.
15. Re-install outer case.
17. Reconnect power supply cord after outer case is installed. Run oven and
check all functions.
18. Carry out “Water load cooking test” again and ensure that oven works proper-
ly.
