Electrolux MCC4060E Service Manual page 25

PROCEDURE
LETTER
L
M
SOI 12.06 FV
TEST PROCEDURES
3. If the fuse F2 F8A is blown, there could be shorts in the asymmetric rectifier
or there is a ground in wire harness. A short in the asymmetric rectifier may
be occurred due to short or ground in H.V. rectifier, magnetron, high voltage
transformer or H.V. wire. Check them and replace the defective parts or
repair the wire harness.
CARRY OUT 4R CHECKS
CAUTION: Only replace fuse F2 F8A with the correct value replacement.
GRILL HEATING ELEMENT TEST (TOP) AND CONVECTION HEATING
ELEMENT TEST
CARRY OUT 3D CHECKS
Before carrying out the following tests make sure the heating element is cooled completely.
1. Resistance of heating element.
Disconnect the wire leads to the heating element to be tested. Using ohmmeter with
low resistance range. Check the resistance across the terminals of the heating
element as described in the following table.
Part name
Grill heating element GH (top)
Convection heating element CH
2. Insulation resistance.
Disconnect the wire leads to the heating element to be tested. check the
insulation resistance between the element terminal and cavity using 500V -
Ω
100M insulation tester. The insulation resistance should be more than 10 M
the cold start.
If the results of above test 1 and/or 2 are out of above specifications, the heating
element is probably faulty and should be replaced.
CARRY OUT 4R CHECKS
CONTROL PANEL ASSEMBLY TEST
The control panel consists of circuits including semiconductors such as LSI, ICs, etc.
Therefore, unlike conventional microwave ovens, proper maintenance can not be
performed with only a voltmeter and ohmmeter.
In this service manual, the control panel assembly is divided into two units, CPU unit and
Power Unit, and troubleshooting by replacement is described according to the symptoms
indicated.
1. Jog Switch Unit Note: Check Jog and Switch unit wire harness
connection before replacement. The following symptoms indicate a
defective Jog Switch unit. Replace the Jog Switch unit.
1-1. Tact switch
a) When touching the buttons, a certain button produces no signal at all.
b) When touching the buttons, sometimes a button produces no signal.
1-2. Potentiometer
a) When rotating the potentiometer, the cooking mode can not be
selected.
1-3. Encoder
a) When rotating the encoder, the cooking time or the weight of food can
not be entered.
COMPONENT TEST
Table: Resistance of heating element
Approximately 44.4
Approximately 42.5
25/43
Resistance
Ω (22.2Ω x 2)
Ω
599 37 42-75
Ω
in