Duke DSO 500, Service Manual

Page: 37 / 80

37
MAGNETRON COOLING FANS
The magnetron cooling fans, Figure 15, provide
air circulation for cooling the magnetrons and high
voltage transformer. This is a twin blower fan.
Location and Access
The magnetron cooling fans are located on the
top front of the oven under the top panel. The top
panel will need to be removed.
Figure 15. Magnetron Cooling Fans
Safety Issues
WARNING
WHEN THE TOP IS REMOVED THE HIGH
VOLTAGE CAPACITOR IS EXPOSED. THE
HIGH VOLTAGE CAPACITOR RETAINS THE
2.5 kVDC CHARGE EVEN AFTER THE OVEN
IS DISCONNECTED. THIS CAPACITOR
MUST BE DISCHARGED BEFORE WORK-
ING ON ANY COMPONENTS IN THE HIGH
VOLTAGE AREA.
• Electrical supply of 208/240 VAC to the
control transformer when POWER switch
is in ON position
• Main POWER switch and fuses have
208/240 VAC present on the input side
whenever the oven is connected to the
input power source
Tools required
• Flat blade screwdriver to remove top
panel of oven
• 3/8 inch nut driver to remove nuts secur-
ing fan to top of oven
Operational Testing
The fan is operational whenever the POWER
switch is in the ON position and any time the
cooling thermostat sees a temperature greater
than 40°C. When the POWER switch is turned
off but cabinet temperature exceeds 40°C the fan
will continue running.
COMPONENT OVERVIEW