31
Service Manual for
RCO Speed Oven
primary side fails and is in a non-conducting condition
(including the interlock system). If the door is slightly
ajar, the primary and secondary interlock switches will
interrupt the magnetron supply currents. Check that the
door operates smoothly and is able to fully close.
Oven Setup Screen
The oven control board is capable of modifying operation
parameters and individualizing parts of the display.
The screens are accessed by pressing the TIME and
TEMP/FAN key simultaneously in the support screen.
Oven setup screen 1
•
Temp Offset
– the setup allows to compensate for
a differential between actual cavity temperatures
(measured with a calibrated thermometer) and the
indicated temperature on the control board.
•
HoldOff Temp
– Allows the user to adjust the
temperature drop before the unit enters recovery
mode. This variable is adjustable from -30 °F to
-70 °F (default).
•
Lock Feature
– allows or disallows editing of
existing recipe settings in the oven by the operator.
•
Set Contrast
– allows change of the contrast of
the display.
Oven setup screen 2
•
Temperature
– determines if temperatures are
displayed in either °F or °C
•
Mag Test
– determines if operator is informed
about magnetron errors or not (all errors are still
recorded in oven stats)
•
Oven Recipes
– allows the user to change between
a 64 or 256 recipe set.
•
Mag XFMR Tap
– shows the current input voltage
of the unit (208 or 240 VAC)
•
Line ADC Sample
– sample taken by the controller
to determine line voltage.
Test Screens
The test screens allow verifying operation of the main
components (magnetrons and convection air system).
They also permit reset statistic counters of errors, etc. The
screens are accessed by pressing the TEMP/FAN and
MICROWAVE key simultaneously in the support screen.
Magnetron Test Screen
The screen allows the operation of the magnetrons
momentarily (i.e. as long as a button is depressed) or a
one minute prolonged test. This can be used to ensure
the control and magnetrons are working accordingly.
During the test, amperage to each Magnetron circuit
can be safely measured on the output of the Solid State
Relay which completes this circuit.
By pressing the SELECT button, the soft keys at
the bottom of the screen change to TEST MAG and
1MIN START. The functionality of the buttons can
be altered back to NEXT and EXIT by pressing the
SELECT button.
The button to test the magnetron serves the purpose
to momentarily test the operation of the magnetron.
The condition should change from OFF to ON shortly
after the button has been depressed.
CAUTION:
Although it is possible to briefly verify
that the magnetrons are energized, the
oven should not be operated without a
load. Microwave energy would be re-
flected back to the magnetron antennas.
This would cause them to overheat and
permanently be damaged, as there is no
load to absorb the microwave energy.
Note:
The diagnostics is a quick identifier if a magnetron
circuit is damaged. However, there might still be cases
where the sensor would indicate a proper supply current,
but the high voltage circuit might not be operating. Refer
to the POWER OUTPUT MEASUREMENT section in
this manual to determine if magnetron output is sufficient
or if a magnetron circuit seems not to be operating.
The button to conduct a one minute test of the magnetron
circuit may be used to conduct a power output test
of the microwave system. As the button is pressed,
the condition of the magnetrons should change from
OFF to ON shortly and a counter should start to count
backwards from 60sec to 0sec.
CAUTION:
The oven should not be operated
without a load. Microwave energy is
reflected back to the magnetron anten
-
nas. The antennas will overheat causing
permanent damage. The energy does
not get absorbed by a load in the cavity.
Fan Test
The second test screen, accessed by pressing the
NEXT button, allows a test of the different blower speed
settings of the oven. By pressing select, the speed
