LG MB-3949G Service Manual page 25

(TROUBLE 4) No microwave oscillation even though oven lamp and fan motor run
CONDITION
No microwave
oscillation.
LGE Internal Use Only
CHECK
Disconnect the
wire leads from
relay 2 and
check continuity
of relay2.
(Operate the
unit)
Check H.V.
transformer.
Check H.V.
capacitor.
Check H.V.
diode.
normal
Check
Abnormal
Magnetron.
RESULT
No continuity.
Continuity.
Abnormal
normal
Abnormal
normal
Defective high
Abnormal
voltage Diode.
Defective
magnetron.
5-15
CAUSE
Defective P.C.B
assembly
Defective high Replace high
voltage voltage
transformer. transformer .
Defective high Replace high
voltage capacitor. voltage capacitor.
Replace high
voltage Diode.
Replace
magnetron .
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
REMEDY
Replace P.C.B
assembly