M Relay Test - Electrolux MCD2660E Service Manual

PROCEDURE
LETTER
L SWITCH UNIT TEST
MC2660E(EU/UK/CH) MC2661E(EU/UK)
ZM266ST (EU/UK) JMW2061 QN4040 EM2612
SW USAGE
1 Start/Quick
2 Not Used
3 Stop
4 Cooking Mode
5 Not Used
6 Auto Defrost
7 Auto Cook plus Grill 2
8 Auto Cook plus Grill 1
9 Auto Cook
M RELAY TEST
SOI 03.06 FV
TEST PROCEDURES
4. Relay Unit
a) Grill cooking is not possible.
If the display fails to clear when the STOP key is depressed, first verify the lead
wire harness is marking good contact, verify that the stop switch operates properly;
that is the contacts are closed when the door is closed and open when the door is
open. If the stop switch is good, disconnect the lead wire harness that connects the
switch unit to the control unit and make sure the stop switch is closed (either close
the door or short the stop switch connecter). Use the switch unit matrix indicated on
the switch unit circuit and place a jumper wire between the pins that correspond to
the STOP key making momentary contact. If the control unit responds by clearing
with a beep the switch unit is faulty and must be replaced. If the control unit does
not respond, it is a faulty and must be replaced. If a specific key does not respond,
the above method may be used (after clearing the control unit) to determine if the
control unit or switch unit is at fault.
Remove the outer case and check voltage between Pin No 1and Pin No 3 of the 3 pin
connector (A) on the control unit with an A.C. voltmeter.
The meter should indicate rated voltage, if not check oven circuit.
RY1,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, dual or grill cooking operation.
DC. voltage indicated ............. Defective relay.
DC. voltage not indicated ....... Check diode which is connected to the relay
RELAY SYMBOL OPERATIONAL VOLTAGE
RY1 Approx. 12.0V D.C.
RY2 Approx. 12.0V D.C.
RY3 Approx. 12.0V D.C.
RY4 Approx. 12.0V D.C.
COMPONENT TEST
coil. If diode is good, control unit is defective.
CONNECTED COMPONENTS
Oven lamp / Turntable motor
Heating element
High voltage transformer
Fan motor
24/38 599 36 78-45