Duke DSO 500, Service Manual

Page: 17 / 80

17
HIGH VOLTAGE RECTIFIERS
The high voltage diodes, Figure 5, rectify the
incoming 2.5 kV voltage and doubles it providing
5kVDC for magnetron operation.
Location and Access
The diodes are located above the top of the cook
chamber at the rear of the oven. The top and side
panels will need to be removed.
Figure 5. High Voltage Rectifiers
Safety Issues
WARNING
THE HIGH VOLTAGE CAPACITOR RETAINS
THE 2.5 kVDC CHARGE EVEN AFTER THE
OVEN IS DISCONNECTED. THIS CAPACI-
TOR MUST BE DISCHARGED BEFORE
WORKING ON ANY COMPONENTS IN THE
HIGH VOLTAGE AREA.
• Electrical supply of 208/240 VAC to trans-
formers when POWER switch is in ON
position and oven doors are closed
Tools Required
• Flat blade screwdriver to remove top and
side panels
• Phillips #2 screwdriver to remove screws
securing diodes to top of oven
• Ohmmeter to check diodes
Operational Testing
The transformers connected to the diodes are
powered from the 208/240 VAC mains sup-
ply through solid state relays K4 and K5 and
mechanical relay K6 and K8. Relays K6 and
K8 are controlled by the door safety interlock
requiring the oven door to be closed to provide
primary voltage to the transformers. The door
safety interlocks interrupt this supply when the
door is opened. Operation of relays K4 and K5
require the POWER switch to be in the ON posi-
tion to provide operating voltage to the control
board. The interlock function can be checked by
opening and closing the oven door and observ-
ing the rotation of the blade on top of the stirrer
motor.
COMPONENT OVERVIEW