background image

 

 

 

 
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. 

- 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 removed less than 

3 mW/cm

2

. Leakage for a fully assembled 

oven (Before the latch switch (primary) is 

interrupted) with the door in a slightly opened 

position-less than 1 mW/cm

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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 1.0 mW/cm

2

. 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 

WARNING : AVOID CONTACTING ANY

HIGH VOLTAGE PARTS 

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

 

5-2 

Содержание MM720CFA-PM0C

Страница 1: ...MICROWAVE OVEN MODEL 700W 220V50Hz SERVICE MANUAL CAUTION BEFORE SERVICING THE UNIT READTHE SAFETY PRECAUTIONS IN THIS MANUAL MM720CFA PM0C...

Страница 2: ...r closing 3 seal and sealing surfaces arcing wear and other damage 4 damage to or loosening of hinges and latches 5 evidence of dropping or abuse C Before turning on microwave power for any service te...

Страница 3: ...M 4 1 CIRCUIT DESCRIPTION 4 2 SERVICE INFORMATION 5 1 TOOLS AND MEASURING INSTRUMENTS 5 1 MICROWAVE LEAKAGE TEST 5 2 MEASUREMENT OF MICROWAVE POWER OUTPUT 5 3 TROUBLE SHOOTING PROCEDURES 5 4 COMMON BR...

Страница 4: ...atch hole and the interlock switches area Unlike other appliances the microwave oven is high voltage and high current equipment Though it is free from danger in ordinary use extreme care should be tak...

Страница 5: ...gth among the molecule and changed to microscopic microwave heating Microwave heating not only concerned the nature of the matter itself but also closely connected with the electric field strength and...

Страница 6: ...and flat 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 BEFORE YOU BEGIN READ THE FOLLOWING INSTRUC...

Страница 7: ...OR CLOSED CONDITION ON SECONDARY BL WH FUSE FILTER ASS Y BR GE BL N L SINGLE PHASE ONLY POWER SUPPLY GE N L BL SWITCH BK NO INTERLOCK MONITOR COM NC M BL TM 2 SWITCH UPPER INTERLOCK PRIMARY BK SWITCH...

Страница 8: ...r is also directed into the oven to exhaust the vapor in the oven through the upper plate Timer starts rotating 3 2 volts AC is generated from the filament winding of the high voltage transformer This...

Страница 9: ...icrowave leakage Check for microwave leakage after every servicing The power density of the microwave radiation leakage emitted by the microwave oven should not exceed 5 mW cm2 Always start measuring...

Страница 10: ...n 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...

Страница 11: ...on the center of the turntable which is in the lowest position and the microwave power switched on The time T for the temperature of the water to rise by a value T of 10 2 K is measured where T is th...

Страница 12: ...Measure the insulating resistance with a multi meter or a mega ohmmeter The value should not less than 2 mega ohm Otherwise part examination should be taken at once Such as checking whether the motor...

Страница 13: ...itor pole and the cabinet FIG 5 6 should be checked If the resistance value between the capacitor pole and the cabinet is the capacitor is normal Then check the earth of the magnetron s two filament t...

Страница 14: ...t the upper screw Loosen out the screw push the door close to the oven to hook the door hook with the plastic parts then tighten the screw again If the leakage is larger at the right below then adjust...

Страница 15: ...cutout is playing its protective role and you should check whether the fan is working in normal Turn off the oven pull out the power plug take down the outer case discharge the capacitor then turn th...

Страница 16: ...Turntable Motor Wire leads removed Measure the resistance Ohm meter scale R 1000 Normal Approx 3 2k Abnormal or Several NOTE z A MICROWAVE LEAKGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS SERVICE...

Страница 17: ...Insert the plug securely 3 Change the weave 5 The oven can heat within 2 3 minutes but can not heat from the fourth minutes 1 The winding of the fan motor in open circuited 2 The fan falls off 3 The...

Страница 18: ...ck the electrical continuity 2 2 Make sure the power cord is pulled out and the high voltage capacitor is discharged before the electrical continuity check 2 3 Set the ohmmeter to Low Resistance range...

Страница 19: ...3 Check the following items before turning the oven ON 1 Proper door closing seal choke surfaces and hinges 2 No outer case damage 3 Proper interlock and monitor operations Insulation Resistance Test...

Страница 20: ......

Страница 21: ...MM720CFA PM0C...

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