Technical information

OM56_Rev G Page 25 of 28
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 ASC Signal 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 5.6m antenna?
In order to move the antenna to stow position, point the antenna to an Elevation angle of 35° (± 3°). The
Azimuth jackscrew should be placed in the center of its travel. In preparation for extreme winds, such as the
approach of a hurricane, antenna should be moved to this position. Stow positioning must be performed
before wind speeds reach 45mph.
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 lacquer
thinner using a soft rag. However, keep in mind that the lacquer thinner 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
Apply a thin coat (approximately .5 to 1 mil) of primer and feather paint it onto the adjacent painted areas.
Allow the primer to dry thoroughly (4-5 hours, depending on environmental conditions) before applying a
finish coat of primer.
Allow the 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).
Thoroughly cover all previously primed areas with paint and blend the paint with any preexisting painted
surfaces.