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5-2

MEASUREMENT WITH OUTER CASE
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.

Special care should be taken in measuring the

following parts. (Circled area of below Fig.)

- Around the magnetron
- The waveguide

MEASUREMENT WITH A FULLY
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.

• 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.

NOTES WHEN MEASURING

• Do not  exceed meter full scale deflection.
• 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.

• 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.

RECORD KEEPING AND NOTIFICATION
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.

• 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.

• At least once a year, have the electromagnetic energy

leakage monitor checked for calibration by its
manufacturer.

WARNING : AVOID CONTACTING ANY

HIGH VOLTAGE PARTS

(Magnetron, H.V. Transformer,
H.V. Capacitor, H.V. Cable Ass’y,
H.V. Circuit Protector)

Содержание MB-392AA

Страница 1: ...MICROWAVE OVEN SERVICE MANUAL MODEL MB 392AA CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL ...

Страница 2: ...ich is graduated to 600 cc and place the beaker on the center of the turntable Set the energy leakage monitor to 2 450 MHz and use it following the manufacturer s recommended test procedure to assure correct result When measuring the leakage always use the 2 inch 5cm spacer supplied with the probe Operate the oven at its maximum output Measure the microwave radiation using and electromagnetic radi...

Страница 3: ...ter than 1 inch sec 2 5 cm sec along the shaded area 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 c...

Страница 4: ...perature is 5 K The microwave power output P in watts is calculated from the following formula is measured while the microwave generator is operating at full power Magnetron filament heat up time is not included about 3 sec The water is stirred to equalize temperature throughout the vessel prior to measuring the final water temperature Stirring devices and measuring instruments are selected in ord...

Страница 5: ...1 Discharge the high voltage capacitor 2 Disconnect the leadwire from magnetron high voltage transformer and capacitor 3 Remove the screw holding the high voltage transformer to the baseplate F FAN MOTOR ASSEMBLY REMOVAL 1 Discharge the high voltage capacitor 2 Disconnect the leadwire from fan motor noise filter and high voltage capacitor 3 Remove the two screws holding the the suction guide ASS Y...

Страница 6: ... 5 mW cm2 With a 275 ml water load Make sure that gasket is rigidly attached to the magnetron To prevent microwave leakage tighten the mounting screws properly making sure there is no gap between the waveguide and the magnetron J REMOVING THE TURNTABLE MOTOR 1 Remove the turntable 2 Remove the Rotating Ring 3 Lay the unit down on its back 4 Remove the turntable motor cover The turntable base cover...

Страница 7: ...SSEMBLY Mount the latch board to the oven assembly Adjust the latch board in the arrow direction so that oven door will not have any play in it when the door is closed Tighten the mounting screw Check for play in the door by pushing the door release button Door movement should be less than 0 5 mm 1 64 inch Don t push the door release button while making adjustment Make sure that the latch moves sm...

Страница 8: ... closed meter should indicate an closed circuit When the secondary switch operation is abnormal make the necessary adjustment or replace the switch only with the same type of switch C MONITOR SWITCH TEST Disconnect the wire lead from the monitor switch Connect the ohmmeter leads to the common COM and normally closed NC terminals of the switch The meter should indicate closed circuit in the door op...

Страница 9: ...S TEST PROCEDURE RESULTS HIGH VOLTAGE TRANSFORMER Wire leads removed MAGNETRON Wire leads removed 1 Measure the resistance Ohm meter scale Rx1 and Rx100 Primary winding Secondary winding Filament winding 2 Measure the resistance Ohm meter scale Rx1000 Primary winding to ground Filament winding to ground 1 Measure the resistance Ohm meter scale Rx1 Filament terminal 2 Measure the resistance Ohm met...

Страница 10: ...r scale Rx1000 Terminal to case Measure the continuity Forward Ohm meter scale Rx10000 Measure the continuity Reverse Ohm meter scale Rx10000 Normal Momentarily indicates several ohms and then gradually returns to infinite Normal Normal Continuity Abnormal Normal Abnormal Continuity NOTE When testing the magnetron be sure to install the magnetron gasket in the correct position and be sure that the...

Страница 11: ...e replacing the fuse If the fuse is blown by improper switch operation replace the defective switch and the fuse at the same time Replace just the fuse if the switches operate normally NOTE Make sure heater is fully cooled when tested Measure the resistance Multi meter scale Rx1 Normal Grill heater Approx 50 Ω at 20 30 C Normal more than 200 MΩ Normal Abnormal Measure the resistance with 500V 100M...

Страница 12: ...e R x 1000 Normal Abnormal or several Ω Normal Approx 100 200 Ω Abnormal or several Ω NOTE A MICROWAVE LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS SERVICED FOR ANY REASON 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 A B C Turn On Turn Off C A B Grill Microwave Approx 22 KΩ Note A is timer ON...

Страница 13: ...el to discharge any static charge built up in your body CONDITION Microwave oven does not work Inserting many plug into one plug outlet and using them at the same time causes overloading Microwave oven plug is not inserted tightly Output power is too low Low AC input voltage Food temperature is too low Using metallic ware and allowing it to touch the oven wall Sparks occurring Inconsistent intensi...

Страница 14: ...ned Disconnect one side of the wire lead connected from transformer to the high voltage capacitor and operate the unit Replace fuse 1 Oven does not operate No continuity No continuity Adjust or replace Malfunction of the primary switch Malfunction of the secondary switch Adjust or replace Check the continuity of the primary switch with door closed Check the continuity of the secondary switch with ...

Страница 15: ...ician Check the power source voltage oscillating No continuity No continuity replace Malfunction of the timer switch Faulty thermostat replace Check the continuity of the timer switch contacts Check the continuity of the thermostat CONDITION CHECK RESULT CAUSE REMEDY TROUBLE 4 Grill CONDITION CHECK RESULT CAUSE REMEDY 1 Heater is not operating Abnormal Normal Normal Heater Thermostat Grill Abnorma...

Страница 16: ...oking state Check the monitor resistor Abnormal Defective AC relay Replace Normal Check the AC relay Abnormal Open the secondary winding of the high voltage transformer of faulty insulation of filament winding Replace Check H V transformer Abnormal Shorted H V diode Replace Check H V diode Abnormal Faulty capacitor Replace Check H V capacitor Abnormal Faulty magnetron Replace Magnetron TROUBLE 5 O...

Страница 17: ... operation of the microwave oven requires that the magnetron be assembled to the waveguide and cavity Never operate the magnetron unless it is properly installed Be sure that the magnetron gasket is properly installed around the dome of the tube whenever installing the magnetron 1 1 CAUTIONS Unlike other appliances the microwave oven is high voltage and high current equipment Though it is free fro...

Страница 18: ...lat surface at least 10 cm 4 inches from the wall 7 Place the microwave oven as far away as possible from TV RADIO COMPUTER etc to prevent interference EARTHING INSTRUCTIONS This microwave oven is designed to be used in a fully earthed condition It is imperative therefore to make sure it is properly earthed before servicing WARNING THIS APPLIANCE MUST BE EARTHED IMPORTANT As the colors of the wire...

Страница 19: ...DOOR PARTS LATCH BOARD PARTS CONTROL PANEL PARTS INTERIOR PARTS BASE PLATE PARTS OVEN CAVITY PARTS 6 1 EXPLODED VIEW INTRODUCTION ...

Страница 20: ...6 2 13581A 14970A 14026A 13552A 13536A 15006A 13213A 13720D 13352A DOOR PARTS ...

Страница 21: ...6 3 23572A 249402 26549T 24781T WTP015 249401 969201 CONTROL PANEL PARTS ...

Страница 22: ...6 4 33112U 35264A WTT021 WTT021 33550H 35026G 33052M 340511 34960A 34036W 36549S WTP013 33390G 35889A 35300S WNZ015 OVEN CAVITY PARTS ...

Страница 23: ...6 5 466003 466001 43501A 43500A 44510A 466002 WSZ085 LATCH BOARD PARTS ...

Страница 24: ...6 6 WSZ002 WTT028 WSZ002 WTT028 WSZ062 50FZZA WSZ002 WTT037 50CZZH 56324A 55262A 54810C 56851C 56851D 55900A 56549F 56411A 56201A 56930V 56930G 568771 54974S 56912B 56201B INTERIOR PARTS ...

Страница 25: ...6 7 56170D 63302A 63303A WTT021 WSZ002 65006B BASE PLATE PARTS ...

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