Measuring Rf Leakage For Microwave Safety; Troubleshooting - TurboChef ngo Service Manual

22 OVEN SYSTEMS

Measuring RF Leakage for Microwave Safety

WARNING: This procedure requires work with
hot surfaces and water loads. To avoid burns, be
careful when testing.
An RF (microwave) leakage test must be performed
at the conclusion of the following service tasks:
- Door removal, replacement and/or adjustment
- Waveguide removal and/or replacement
- Magnetron removal and/or replacement
- Door switch adjustment and/or replacement
WARNING: If the unit fails the microwave
leakage test (leakage greater than 5mW/cm
the oven must be taken out of service
immediately until the defect is corrected. In
addition, the CDRH Regulation 21 Subpart C,
1002.20 requires that leakage readings of over
5mW/cm
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To measure RF leakage,
1. Turn the oven on (page 8) and allow it to warm
up to the set temperature (approximately 15
minutes if the oven starts cold).
2. Once the oven has warmed up, place the oven
in Test Mode (see page 14). From Test Mode,
select Manufacturing Mode.
3. From the Manufacturing Mode screen, select
"MW Leak Test" and follow the instructions on
the screen (also detailed in the following steps).
4. Place a water load into the cook cavity. The
water load must conform to the following
specifications:
- Volume: 275 ml ± 15 ml
- Temperature: 68 º F ± 9 º F (20 º C ± 5 º C)
- Vessel: Low form, 600 ml beaker with an
inside diameter of approximately 3.35" (85
mm) and made of Pyrex or equivalent.
5. Close the oven door and press the Enter key.
The microwave system will turn on.
6. Measure microwave emission around the door as
shown in Figure 29, moving the meter sensor at
0.5 inches/second.
must be reported to the manufacturer.
7. As microwave leakage is observed while moving
the sensor, note any meter spike areas that come
close to 5mW/cm
8. Replace the water load every 60 seconds until
the test is completed, and also after scanning
the door.
9. Close the oven door and return the meter probe
to any "meter spike" areas and allow the probe to
remain in the "spike" area for 17 seconds. Note
the highest reading obtained.
NOTE: There may be several places on the door
where this procedure needs to be done. If so, start
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out with a fresh water load each time a new area is
measured, or if measurement of an area takes longer
than 60 seconds.
10. After each test is complete, open the oven door
and dispose of the hot water.
Figure 29: Survey Meter Placement

Troubleshooting

The following faults may occur in relation to the
oven door:
- F4: Monitor (see page 36)
The following issues may occur in relation to the
oven door:
- "Cook Door Open" message when door is
closed (see page 39)
for later re-measurement.
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