Relay Test - Wolf MWD24-2 Service Manual

Troubleshooting Guide
PROCEDURE LETTER
C
#813632 - Revision B - December, 2009
Drawer Microwave

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.
RELAY SYMBOL OPERATIONAL VOLTAGE
RY1
RY2
RY3
RY4
RY5
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.
5-6
(Models MWD24-2 / MWD30-2)
COMPONENT TEST
Approx. 26 vdc
Approx. 25 vdc
Approx. 26 vdc
Approx. 26 vdc
Approx. 26 vdc Switching regulator or drawer motor
CONNECTED COMPONENTS
Oven lamp / Common
Power transformer
Stirred motor
Fan motor