Service Manual for
RCO Speed Oven
32
settings for both convection blowers from zero to nine
can be accessed and verified. The oven door has to
remain closed for this test.
Note:
The blower speed cannot be set to zero during
operation.
Clear Counts
This screen is accessed by pressing the NEXT button,
allows the reset of all indicated counters by pressing
SELECT once.
Press EXIT to exit the test screens.
Microwave Leakage Test
Every microwave oven strictly has to fulfill the
requirement that microwave leakage does not exceed
4mW/cm² at any point around the chassis, especially
around the door. In addition, the leakage reading must
be documented on the service repair documentation.
Check for radiation leakage after servicing. If the
leakage exceeds 4mW/cm², REMOVE OVEN FROM
OPERATION / SERVICE, and contact Duke Service
immediately. After repairing or replacing any radiation
safety device, keep a written record for future reference,
as required by FDA/DHHS and Health and Welfare
Canada regulations.
Tools Required For Microwave Leakage Test
• 600ml low form, glass beaker (preferably Pyrex
glass), having an inside diameter of approximately
3.35" (8.5cm)
• Supply of cold tap water, initial temperature should
be 59°F - 77°F (15°C - 25°C)
• Leakage Survey Meter
Note:
The door can be pulled by hand and held in
a position that prevents the interlock switches from
disengaging. This allows microwaves to be generated
despite the door being slightly opened.
Note:
Read and understand the following notes and
the procedure, before performing the measurements.
Note:
Refer to user manual of the Microwave Survey
Meter for proper operation.
• Make sure that the survey meter you are using
has been calibrated and is suitable for measuring
frequencies of 2.45GHz.
• Do not exceed meter full scale deflection. Leakage
meter should initially be set to the highest scale.
• Adjust to lower scales to ensure that low readings
are measured on the most sensitive range.
• Set probe sensitivity to “slow” setting.
ON A USED OVEN THE LEAKAGE
AROUND DOOR SHOULD NOT EXCEED 4mW/
cm².
When measuring the leakage, use the probe supplied
with the instrument. Always hold the probe at right
angle to the oven and the point of measurement.
Measuring Procedure
1. This test should be performed both at 500 °F
(260°C) and 375 °F (191°C), not just at the oven
set point.
2. Pour 9.2 fl. oz +/- .5fl. oz (275mL +/- 15mL) into a
600 mL Pyrex beaker.
3. Place the beaker in the center of
oven.
Note:
Water must be replaced every 30 seconds to
prevent boiling. If water boils leakage measurements
will be inaccurate.
CAUTION:
Water will be extremely hot after cook
cycle. Wear hand and eye protection
when handling hot water.
4. Close the door and set manual cook time for 30
seconds, fan speed 1, and set microwave to 100%
output.
5. Move probe head around perimeter of door frame
and oven chassis at a pace no greater than 1"/sec
(2.5cm/s). Record the highest leakage valve.
6. Using the same procedure, pull the door open
by hand to the outmost position that still allows
microwaves to be generated and record the
highest leakage valve.
TIP:
To hold the door open for this test, grasp the
center of the door handle and with your thumb
pressing against the door handle for leverage,
carefully pull the door.
Note:
Switch/relay is not to disengage at this point to
ensure magnetron operation.
7. Repeat Leakage Test for all louver openings.