Sea Tel Side Exit, Quick Start Manual, Page: 5 / 9

Procedure, Field Replacement, Level Cage Kit, Side Exit
Page 4 of 8
Document No
135265 Rev B
Copyright © Sea Tel, Inc 2011 - The information contained in this document is proprietary to Sea
Tel, Inc.. This document may not be reproduced or distributed in any form without prior written
consent of Sea Tel, Inc.
10. Diagnostics:
Any incorrect readings from the above tests would relate to an error in the antennas control loop causing the system to
not stabilize correctly. The most likely cause of this is a defective sensor in the level cage. The next step would be to
replace and re ‐ calibrate the level cage. Now repeat the failed test to verify that the system is now functioning correctly.
Should the problem remain, another possible cause may be a fault with the reference harness between the level cage
and PCU. The PCU itself should not be ruled out as faulty either. Even so, the level cage is the most likely component to
be causing this issue, therefore replacing it is the first step when troubleshooting.
Once the problem has been rectified, it is good practice to refit the original level cage and see if the fault returns. It is
possible that corrosion on the pins of the reference harness and/or connectors of the PCU/level cage caused the initial
fault. By connecting the replacement level cage, it is likely that any pin corrosion may have rubbed off, creating a cleaner
electrical contact. You may have been under the impression that replacing the level cage rectified the fault when in
actual fact; the issue was a poor electrical contact causing varying resistance.
11. Further Information:
Should the system fail to target the correct elevation (physically pointing at a different position to the reading on the
DAC), or have issues driving past a certain elevation position then the most likely cause is a defective level cage motor.
If the system is displaying a pedestal error (error 8), there is a drive issue with the antenna and attention will need to be
paid to the motor and motor driver (servo amp) for the relevant axis. There is no error code that directly tells you if the
level cage or level cage stepper motor has failed, however, a pointing or stabilization issue is a good indication.
Another potential issue which could cause the antenna to lose the satellite is if the vessels gyro compass is drifting. This
accumulating error is then fed into the control loop. This can be verified by running a DacRemP log file at sea to monitor
the pedestals readings when the AGC drops, or by putting the system into satellite reference mode to uncouple the gyro
feed from the azimuth stabilization loop.