BIRD 8135 Operation Manual - Rf Assembly Test
Maintenance
9
RF Assembly Test
DC Resistance - Check the condition of the load resistor by accurate
measurement of the DC resistance between the inner and outer conductors of
the RF input connector. Use a resistance bridge or ohmmeter with an accuracy
of one percent or better at 50 ohms for this purpose. The measured resistance
should be nominal 50 ohms. For greater accuracy, the resistance of the load
should be carefully checked prior to use at ambient room temperature. This
resistance value should be recorded and used as a reference. Subsequent
resistance measurements should not deviate more than two percent from this
value.
Disassembly
There are no special techniques required for the repair or replacement of
components in the Model 8135 Termaline Load. A screwdriver is the only tool
needed. The paragraphs below outline component removal.
RF Input Connector Replacement
The input connector is a patented “Quick-Change” design which permits easy
interchange with the use of only a screwdriver. This process does not interfere
with the essential coaxial continuity of the load resistor RF input or the coolant
oil seal. For replacement, proceed as follows:
1.
Remove the four 8-32 x 5/16 inch round head machine screws from the
corners of the RF connector.
2.
Pull the connector straight out of its socket.
Diaphragm and Coolant Oil
Remove the diaphragm to replace or examine the coolant oil. Replacement of
the diaphragm and coolant oil are outlined in the following steps:
1.
Stand the load vertically, with the back end up.
2.
Loosen the clamp screw until clamping band is released.
3.
Remove the diaphragm cover and lift diaphragm from back end of radiator
tank. If the diaphragm is no longer pliable or shows signs of surface cracks,
replace it.
4.
The coolant oil level should be about one inch below the top of the radiator
cylinder. If the oil appears to be contaminated, replace it.