Bird Technologies 8890-320 Series - Manual (Page 26)

14
Maintenance
Cleaning the Load
Cleaning the Load Resistor
•
The outside surface of the instrument should be wiped free of dust and dirt when necessary.
•
Clean the cooling fins.
Note: Excessive dust on the cooling fins will interfere with heat dissipation.
•
Clean the RF connector, both metallic and insulating surfaces, with a dry, non-residue forming solvent.
Cleaning the Blower Assembly
•
The intake grills, fans, and inside of the baffles should be wiped free of dust and dirt when necessary.
Note: Excessive dust will interfere with heat dissipation.
When the blower assembly is installed, it will be necessary to partially disassemble the blower to clean the load’s
radiator fins.
1. Unscrew both 10-32 truss head screws that secure one of the side baffles and remove it.
2. Clean the load
3. Secure the side baffle with the 10-32 truss head screws.
4. Repeat Steps 1-3 for the other side baffle.
Inspecting the Load
•
Inspect the unit every six months.
a.
Check for coolant leakage around the clamping band.
b. Check for coolant leakage around the thermoswitch.
c. Check for corrosion.
Measuring the 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 load resistor’s condition. Under normal operating conditions, the resistor should pro-
vide 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.
WARNING
Do not operate with side panel removed. Doing so could result in personal injury.
WARNING
Never attempt to connect or disconnect RF equipment from the transmission line while RF power is being applied.
Leaking RF energy is a potential health hazard.