Drawer Microwave
(Models MWD24-2 / MWD30-2)
Troubleshooting Guide
5-6
#813632 - Revision B - December, 2009
C
RELAY 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.
4. Disconnect the leads to the primary of the power transformer.
5. Ensure that these leads remain isolated from other components and oven
chassis by using insulation tape.
6. After that procedure, re-connect the power supply cord.
7. Remove the outer case and check voltage between Pin Nos. 5 and 7 of the 4
pin connector (CN-A) on the power unit with an A.C. voltmeter.
The meter should indicate 120 volts, if not check oven circuit.
RY, RY2, RY3 and RY4 Relay Test
These relays are operated by D.C. voltage
Check voltage at the relay coil with a D.C. voltmeter during the microwave
cooking operation.
•
DC. voltage indicated Defective relay.
•
DC. voltage not indicated Check diode which is connected to the relay
coil. If diode is good, control unit is defective.
COMPONENT TEST
PROCEDURE LETTER
RELAY SYMBOL
OPERATIONAL VOLTAGE
CONNECTED COMPONENTS
RY1
Approx. 26 vdc
Oven lamp / Common
RY2
Approx. 25 vdc
Power transformer
RY3
Approx. 26 vdc
Stirred motor
RY4
Approx. 26 vdc
Fan motor
RY5
Approx. 26 vdc
Switching regulator or drawer motor
8. Disconnect the power supply cord, and then remove outer case.
9. Open the door and block it open.
10. Discharge high voltage capacitor.
11. Reconnect all leads removed from components during testing.
12. Re-install the outer case (cabinet).
13. Reconnect the power supply cord after the outer case is installed.
14. Run the oven and check all function.