Maintenance
11
Replace RF Connector
Note:
Tool required:
Screwdriver
The following paragraphs outline the component removal and replacement procedure.
The connector is a Quick-Change (QC) design which permits easy interchange with the use of only a screwdriver.
This process does not interfere with the essential coaxial continuity of the attenuator RF input, out put, or the
coolant oil seals. For replacement, proceed as follows:
1.
Remove and retain the four screws from the corners of the RF connector.
2.
Pull the connector straight out of its socket.
3.
Insert the new connector into the mating connector. Be sure the projecting center pin on the connector is
properly engaged and seated in the mating socket, then push it in firmly.
4.
Install the four screws that were previously removed.
Maintaining Coolant Level
The level of the dielectric coolant should remain constant in the unit after prolonged usage under normal operating
conditions. As shipped, the coolant is at a factory determined level, and should be about 3-1/4" (82.5mm) below
the surface of the thermoswitch hole, with the unit in a vertical position. However, loss of up to 10% of the full tank
capacity should not impair the operating efficiency of the attenuator.
Inspecting Coolant
The coolant should be a light yellow color.
Note:
If it is dark and not a light yellow, it may be contaminated and should be replaced.
Inspect, occasionally, around the clamping band at the input end for possible coolant leakage.
Tighten the clamping screw, if necessary
Ensure the O-Ring seal is in good condition; i.e., soft and pliable and free from surface cracks.
Adding Coolant
Add coolant through the pipe plug hole (thermoswitch hole) until it reaches the proper level, about 3-1/4 inches
below the surface of the hole.
Note:
Do not overfill the unit beyond the recommended level.
Replacing Coolant
1.
Remove the rear (output) connector.
2.
Replace the vent plug with the shipping plug.
3.
Raise the unit, carefully, by its front handle and foot until it is tipped up on its back.
4.
Position the load on the bench top so that the entire rear connector assembly, minus the connector, projects
over the edge of the bench.
5.
Brace the unit vertically in this position so that it will not topple over.
6.
Place a clean container for liquid just under the rear connector assembly to receive the coolant.
Note:
The volume of the coolant is 2.9 gallons (11 liters), so the container must be at least a three gal-
lon size, and preferably five gallons.
7.
Remove the V-band clamp from around the front (input) connector assembly by loosening the 10-32 holding
screw sufficiently to slip the band off.
8.
Work the RF section assembly loose and, carefully, lift it straight out of the resistor tank.
Note:
There will be some initial resistance as the O-Ring seal around the rear connector assembly
comes loose from the housing.
