LG Microwave Oven MS3447GR User Manual

5-14

(TROUBLE 3) Display shows all figures set, but oven does not start cooking while desired

program times are set and START pad is touched.

(TROUBLE 4) Oven seems to be operating but little heat is produced in oven load.

CONDITION

CHECK

RESULT

CAUSE

REMEDY

1.Setting time

does not count
down when
touching START
pad.

2. Fan motor or

oven lamp do
not turn on.

No continuity.

Continuity.

Continuity

No continuity

Check the con-
nection between
CN1 connector
and PCB
assembly.

Defective
secondary switch.

Replace
secondary switch.

Defective PCB
assembly.

Replace PCB
assembly.

Check continuity
of secondary
switch (with
door closed).

Check fan motor.

Check oven lamp.

Abnormal.

Normal.

Defective fan motor.

Defective oven lamp.

Replace fan motor.

Replace oven lamp.

Loose connection.

Connect them
tightly.

CONDITION

CHECK

RESULT

CAUSE

REMEDY

Output is low.

Lower than 90% of
rating voltage.

Normal.

Abnormal.

Measure the
output power.

Disconnect the
wire leads from
relay 2 and
check on and off
time with
multitester.

Defective PCB
assembly.

Replace PCB
assembly.

Decrease in power
source voltage
with load.

Suggest customer
contact local
electric power
utility co. or
qualified
electrician.

Check the
power source
voltage.

Defective
magnetron.

Replace
magnetron.

NOTE: Simple test of power output-conducted by heating one liter water for one min. if available.

Minimum 8.5˚C temperature rise is normal condition.

LGE Internal Use Only