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5.0 Corrective Maintenance & Troubleshooting
The following sections will offer information, instructions, and guidelines regarding issues of corrective
maintenance such as painting, backlash adjustment, and maintenance kits.
5.1 Top 5 ESA Maintenance & Troubleshooting FAQ
1.
What should be done about chips, cracks, scratches, etc., in the paint of the reflector and/or other
ESA surfaces?
Priming and/or painting certain surfaces of the ESA is permitted and advisable under specific conditions such as
gouges, scratches, etc. in the surface of the reflector paint (refer to
Section 5.2
for detailed instructions).
2.
How can I remove Backlash?
Backlash is removed by performing anti-backlash Jack Adjustment (for detailed instructions, see
Section 5.3
)
3.
Are there any particular kits available for purposes of maintenance?
A number of maintenance kits are available for this particular antenna. A list of these kits may be found in
Table
5.1
(refer to
Section 5.4
).
4.
Are there any particular precautions that can be taken to avoid damaging the feed window?
All
Kratos
ESA feed windows are rated at .5 psi. This means placing any pressure on the feed window of
more
than .5 psi is likely to cause permanent damage to feed window, which will require replacement.
5.
What is the proper stow procedure for the 4.5m antenna?
For telescoping strut type mounts, verify all set screws are securely tightened (minimum of 50 ft-lbs) on the
Azimuth and Elevation struts. For threaded rod strut type mounts, fully retract the threaded rod into the Az and
El strut pipes. The Azimuth strut should be placed in the center of its travel. Please note that stow positioning
must be performed
before
wind speeds reach 65mph, otherwise the motors may not function.
5.2 Corrective Painting Instructions
The following sections offer detailed instructions for corrective painting of particular surfaces on the Earth Station
Antenna. Please keep in mind that only qualified personnel should be allowed to perform these procedures. Also,
be certain to
read all of the following sections thoroughly
BEFORE
proceeding
.
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5.2.1 Preparatory Cleaning of Aluminum Surfaces
Remove all loose paint and/or rust from the surface to be painted using a scraper, wire brush, or steel wool.
If steel wool is used, take care to ensure that none of it is left on the reflector or feed horn window after
cleaning (steel wool tends to leave behind particles). Wipe the surface to be painted with acetone using a
soft rag. However, keep in mind that the acetone will also dissolve the surrounding paint if used too heavily
and/or rubbed too hard. Paint edges can be blended to the metal using very fine grit sandpaper. If necessary,
the surface of the reflector may be washed clean using plain water.
IMPORTANT NOTE:
Do NOT use bleach, soap, cleaning solutions, or kerosene, as these substances leave behind residue
that is difficult to remove.
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5.2.2 Priming Cleaned Aluminum Surfaces
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Apply a thin coat (approximately .5 to 1 mil) of primer and feather paint it onto adjacent painted areas
•
Allow primer to dry thoroughly (4-5 hours, depending on environmental conditions) before applying a
finish coat of primer
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Allow finish coat of primer to dry thoroughly (8-12 hours) before proceeding
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5.2.3 Painting Primed Aluminum Surfaces
For antenna surfaces, such as the front or back of the main reflector or subreflector, high-reflectivity white
paint should be used. This type of paint disperses light rays. The paint may be applied to the prepared area
using a brush, roller, or sprayer. If a sprayer is used, be sure to first thin the paint to a proper consistency
with paint thinner (10-15% thinner).
