Whirlpool 721.663398 Microwave Oven User Manual


 
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CONDITION CHECK RESULT CAUSE REMEDY
No microwave
oscillation.
No continuity.
Continuity.
Abnormal
Defective high
voltage
transformer.
Replace high
voltage
transformer.
Normal
Defective PCB
assembly.
Replace PCB
assembly.
Disconnect the
wire leads from
relay 2 and
check continuity
of relay 2.
(Operate the unit)
Check high vol-
tage transformer
Output is full power
when you set lower
power level.
Abnormal.
Defective PCB
assembly.
Replace PCB
assembly.
Disconnect the
wire leads from
relay 2 and check
continuity relay 2.
(Operate the unit)
Abnormal
Defective high
voltage capacitor.
Replace high
voltage capacitor.
Normal
Check high vol-
tage capacitor.
Abnormal
Defective high
voltage diode.
Replace high
voltage diode.
Normal
Check high vol-
tage diode.
Abnormal
Defective
magnetron.
Replace
magnetron.
Check
magnetron.
(TROUBLE 5)
No microwave oscillation even though oven lamp and fan motor run.
(Display operates properly)
NOTE : • Make sure the wire leads are in the correct position.
• When Removing the wire leads from the 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.