LG MB-4342A Service Manual page 26

(TROUBLE 5) No microwave oscillation even though oven lamp and fan motor run
(Display operates properly)
CONDITION
No microwave
oscillation.
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.
Check
Magnetron.
RESULT
No continuity.
Continuity.
Abnormal
normal
Abnormal
normal
Abnormal
normal
Abnormal
5-16
CAUSE
Defective P.C.B
assembly
Defective high
voltage
transformer.
Defective high
voltage capacitor.
Defective high
voltage Diode.
Defective
magnetron.
REMEDY
Replace P.C.B
assembly
Replace high
voltage
transformer .
Replace high
voltage capacitor.
Replace high
voltage Diode.
Replace
magnetron .