LG MS-256NB Service Manual ▷ View online
6-7
633031
633021
56170D
647781
WTT030
WSZ062
WSZ002
WTT021
BASE PLATE PARTS
5-15
CONDITION
CHECK
RESULT
CAUSE
REMEDY
No microwave
oscillation.
oscillation.
No continuity.
Continuity.
Abnormal
Defective high
voltage
transformer.
voltage
transformer.
Replace high
voltage
transformer.
voltage
transformer.
Normal
Defective PCB
assembly.
assembly.
Replace PCB
assembly.
assembly.
Disconnect the
wire leads from
relay 2 and
check continuity
of relay 2.
(Operate the unit)
wire leads from
relay 2 and
check continuity
of relay 2.
(Operate the unit)
Check high vol-
tage transformer.
tage transformer.
Abnormal
Defective circuit
protector.
protector.
Replace circuit
protector.
protector.
Normal
Check circuit
protector.
protector.
Abnormal
Defective high
voltage capacitor.
voltage capacitor.
Replace high
voltage capacitor.
voltage capacitor.
Normal
Check high vol-
tage capacitor.
tage capacitor.
Abnormal
Defective high
voltage diode.
voltage diode.
Replace high
voltage diode.
voltage diode.
Normal
Check high vol-
tage diode.
tage diode.
Abnormal
Defective
magnetron.
magnetron.
Replace
magnetron.
magnetron.
Check
magnetron.
magnetron.
(TROUBLE 5) No microwave oscillation even though oven lamp and fan motor run.
(Display operates properly)
5-16
Output is full power
when you set lower
power level.
when you set lower
power level.
Abnormal.
Defective PCB
assembly.
assembly.
Replace PCB
assembly.
assembly.
Disconnect the
wire leads from
relay 2 and check
continuity relay 2.
(Operate the unit)
wire leads from
relay 2 and check
continuity relay 2.
(Operate the unit)
NOTE : • Make sure the wire leads 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
• When removing the magnetron, be sure to install the magnetron gasket in the correct position
and in good condition.
CONDITION
CHECK
RESULT
CAUSE
REMEDY
(TROUBLE 5) No microwave oscillation even though oven lamp and fan motor run.
(Display operates properly)
MEASUREMENT WITH OUTER CASE
REMOVED
REMOVED
• When you replace the magnetron, measure for
microwave energy leakage before the outer case is
installed and after all necessary components are
replaced or adjusted.
installed and after all necessary components are
replaced or adjusted.
Special care should be taken in measuring the
following parts. (Circled area of below Fig.)
- Around the magnetron
- The waveguide
- The waveguide
MEASUREMENT WITH A FULLY
ASSEMBLED OVEN
ASSEMBLED OVEN
• After all components, including the outer case, are fully
assembled, measure for microwave energy leakage
around the door viewing window, the exhaust opening,
and air inlet openings.
around the door viewing window, the exhaust opening,
and air inlet openings.
• Microwave energy leakage must not exceed the values
prescribed below.
NOTE: Leakage with the outer case removedless than
5 mW/cm.sq. Leakage for a fully assembled
oven (Before the latch switch (primary) is
interrupted) with the door in a slightly opened
position-less than 2 mW/cm.sq.
oven (Before the latch switch (primary) is
interrupted) with the door in a slightly opened
position-less than 2 mW/cm.sq.
NOTES WHEN MEASURING
• Do not exceed meter full scale deflection.
• The test probe must be removed no faster than
• The test probe must be removed no faster than
1 inch/sec (2.5 cm/sec) along the shaded area,
otherwise a false reading may result.
otherwise a false reading may result.
• The test probe must be held with the grip portion of the
handle.
A false reading may result if the operator's hand is
between the handle and the probe.
• When testing near a corner of the door, keep the probe
perpendicular to the surface making sure the probe
horizontally along the oven surface, this may possibly
cause probe damage.
horizontally along the oven surface, this may possibly
cause probe damage.
RECORD KEEPING AND NOTIFICATION
AFTER MEASUREMENT
AFTER MEASUREMENT
• After adjustment and repair of any microwave energy
interruption or microwave energy blocking device,
record the measured values for future reference. Also
enter the information on the service invoice.
record the measured values for future reference. Also
enter the information on the service invoice.
• The microwave energy leakage should not be more
than 4 mW/cm.sq. after determining that all parts are in
good condition, functioning properly and genuine
replacement parts which are listed in this manual have
been used.
good condition, functioning properly and genuine
replacement parts which are listed in this manual have
been used.
• At least once a year, have the electromagnetic energy
leakage monitor checked for calibration by its
manufacturer.
manufacturer.
5-2
WARNING : AVOID CONTACTING ANY
HIGH VOLTAGE PARTS
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