20
5. Alignment and Adjustments
5-10 Procedure for Measurement of Microwave Energy Leakage
1.
Pour 275±15cc of 20±5°C(68±9°F) water in a beaker which is graduated to
600cc, and place the beaker in the center of the oven .
2.
Start to operate the oven and measure the leakage by using a microwave
energy survey meter .
3.
Set survey meter with dual ranges to 2,450MHz .
4.
When measuring the leakage, always use the 2 inch spacer cone with the
probe . Hold the probe perpendicular to the cabinet door . Place the spacer
cone of the probe on the door and/or cabinet door seam and move along
the seam, the door viewing window and the exhaust openings moving the
probe in a clockwise direction at a rate of 1 inch/sec . If the leakage testing of the cabinet door seam is taken near
a corner of the door, keep the probe perpendicular to the areas making sure that the probe end at the base of the
cone does not get closer than 5cm to any metal . If it gets closer than 5cm, erroneous readings may result .
5.
Measured leakage must be less than 4mW/cm2 , after repair or adjustment .
Maximum allowable leakage is 5mW/cm2 .
4mW/cm2 is used to allow for measurement and meter accuracy
5-11 Check for Microwave Leakage
1.
Remove the outer panel .
2.
Pour 275±15cc of 20±5°C(68±9°F) water in a beaker which is graduated to 600cc,
and place the beaker in the center of the oven .
3.
Start the oven at the highest power level .
4.
Set survey meter dual ranges to 2,450MHz .
5.
Using the survey meter and spacer cone as described above, measure near the
opening of magnetron, the surface of the air guide and the surface of the wave
guide as shown in the following photo .( but avoid the high voltage components .)
The reading should be less than 4mW/cm2 .
5-12 Note on Measurement
1.
Do not exceed the limited scale .
2.
The test probe must be held on the grip of the handle, otherwise a false reading may result when the operator’s
hand is between the handle and the probe .
3.
When high leakage is suspected, do not move the probe horizontally along the oven surface; this may cause
damage to the probe .
4.
Follow the recommendation of the manufacturer of the microwave energy survey meter .
