Bird Technologies 8640B Series - Manual (Page 25)

Bird 8640 Series Moduload RF Load Resistor
14
Maintenance
Cleaning
The outside surface of the unit should be wiped free of dust and dirt
when necessary. Clean the RF connector, both metallic and insulating
surfaces, with a dry, non-residue forming solvent.
If dust has collected on the radiator coils, remove the top panel and
vacuum the coils. To remove the panel:
y Remove the screws around the edge of the top panel.
y Lift the top panel to access the fan power connector then
disconnect the fan cable.
y Remove the top panel.
Inspection
Routinely check the load’s center and outer conductors for visible
damage or excessive wear. The coolant level should be checked once a
week, more often if the Moduload is used continuously or under high
ambient temperatures. The coolant level should be above the min.
mark on the gauge even when the unit is on. To add coolant, see
“Changing Coolant” on page 15.
DC Resistance
Measuring the dc resistance between the inner and outer conductors
of the RF connector shows changes in the load over time, a good check
of the resistor’s condition. Under normal operating conditions, the
resistor should provide at least 5,000 hours of operation before
requiring any additional service. DC resistance tracking must start
before the load is put into service, and should be measured annually.
Perform the following steps and record the value for future
comparison. Make sure that you have an ohmmeter with an accuracy
of ±1% at 50 ohms and that the load temperature is between 20 and
25 °C (68 to 77 °F) before starting.
WARNING
Disconnect the unit from all power sources before servicing.
The unit may be energized from multiple sources.
The potential for electric shock exists.