LG MC-7642W Service Manual page 28

(TROUBLE 6) Oven does not cook properly when programmed for the set power level
(Operates properly on HIGH)
CONDITION
Output is full when
you set lower
power level.
(TROUBLE 7) Grill/Convection
CONDITION
1. Heater is not
operating.
2. Under or over
cooking in conv.
mode.
NOTE: * Make sure the wore leads correct position.
* When removing the wire leads from parts be sure to grasp the connector not the wires.
* When removing the magnetron, be sure to install the magnetron gasket in the correct position and in
good condition.
CHECK
Disconnect the
wire leads from
relay 2 and check
continuity relay 2.
(Operate the unit)
CHECK
Heater.
Relay3, 5.
Wire connection.
Heater.
Thermistor
RESULT
Abnormal.
RESULT
Abnormal.
Normal.
Abnormal.
Normal.
No continuity.
Abnormal.
Normal.
Abnormal.
5-18
CAUSE
Defective P.C.B.
assembly.
CAUSE
Malfunction the
heater.
Malfunction the
relay.
Open or loosen.
Malfunction the
heater.
Malfunction the
thermistor.
REMEDY
Replace P.C.B.
assembly.
REMEDY
Replace.
Replace.
Replace or
connect tightly.
Replace.
Replace.