LG MB-4334B, Service Manual

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5-14
CONDITION CHECK RESULT CAUSE REMEDY
CONDITION CHECK RESULT CAUSE REMEDY
1.Setting time does
not count down
when touching
START pad.
No continuity.
Continuity.
Defective
secondary switch. Replace
secondary switch.
Check continuity
of secondary
switch (with
door closed).
Check continuity
of secondary
switch (with
door closed).
2. Fan motor or
oven lamp do
not turn
on.
No continuity.
Defective fan
motor. Replace fan
motor.
Check fan motor.
No continuity.
Defective oven
lamp. Replace oven
lamp.
Check oven lamp.
Normal.
No continuity.
Continuity.
Defective P.C.B
assembly. Replace P.C.B
assembly.
Loose connection.
Connection then
tightly.
Output is low.
Lower than 90% of
rating voltage.
Normal.
Decrease in power
source voltage
with load.
Suggest customer
contact local
electric power
utility co. or
qualified
electrician.
Check the
power source
voltage.
Disconnect the
wire leads from
relay 2 and check
on and off time
with multitester.
Abnormal.
Abnormal.
Abnormal.
Defective
magnetron. Replace
magnetron.
Defective P.C.B
assembly. Replace P.C.B
assembly.
Measure the
Abnormal. output.
(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 operation but little heat is produced in oven load.
NOTE: Simple test of power output-conducted by heating one liter water for one min. if available.