LG LMVH1711ST Service Manual page 38

(TROUBLE 5) No microwave oscillation even though oven lamp and fan motor run
(Display operates properly)
CONDITION
No microwave
oscillation.
Check high vol-
tage diode.
Check
Magnetron.
NOTE: * Make sure the wire leads are in the 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.
Output is full power
when you set lower
power level.
CHECK
Disconnect the
No continuity.
wire leads from
relay 8 and
check continuity
Continuity.
of relay 8.
(Operate the
unit)
Check high vol-
Abnormal
tage transformer
normal
Check high vol-
Abnormal
tage capacitor.
normal
Abnormal
normal
Abnormal
Disconnect the
Abnormal.
wire leads from
relay 8 and check
continuity relay 8.
(Operate the unit)
RESULT
Defective P.C.B
assembly
Defective high
voltage
transformer.
Defective high
voltage capacitor.
Defective high
voltage Diode.
Defective
magnetron.
Defective PCB
assembly.
7-26
CAUSE REMEDY
Replace P.C.B
assembly
Replace high
voltage
transformer .
Replace high
voltage capacitor.
Replace high
voltage Diode.
Replace
magnetron .
Replace PCB
assembly.