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I'm currently facing a little problem with our Yaesu controller. I have done all the calibration and the controller appears to be working fine. Unfortunately, it does so for short duration (a couple of hours maybe). After that, the azimuth control goes askew with an offset of around 15 degrees. Therefore I had to recalibrate it almost every time before I try to communicate with any satellite. Could you please provide advice in case you have encountered a problem like this before? I use GPredict and rotctld for all the control.

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  • $\begingroup$ Is the calibration done in software, or by adjusting potentiometers in the control box? $\endgroup$ – rclocher3 Jul 18 '16 at 16:22
  • $\begingroup$ Also, does the controller misbehave even with the computer disconnected from it? $\endgroup$ – user157 Jul 19 '16 at 11:43
  • $\begingroup$ Hello. The calibration is done in hardware first and then in software. I recalibrated everything[hw and sw] and it seemed to work fine. However, it has started to misbehave again in both hw and sw. $\endgroup$ – Moses Browne Mwakyanjala Jul 21 '16 at 13:47
  • $\begingroup$ I know this is an old thread but if you are still struggling with this... Does the azimuth calibration change on both the meter and for the computer or only for the computer? $\endgroup$ – Glenn W9IQ Jun 26 '17 at 17:28
  • $\begingroup$ The azimuth calibration changes on both. $\endgroup$ – Moses Browne Mwakyanjala Jul 18 '17 at 13:59
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I had the same issue. I adjust the Azimuth every day, then sometimes it fails between 15-20 degrees.

Then I replaced the regulator with a new one. Now it is ok.

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  • $\begingroup$ Welcome to ham.stackexchange.com! It's nice to get an answer from someone with direct, practical experience of the problem. $\endgroup$ – rclocher3 Jul 28 at 22:32
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Sorry for the long overdue reply but you didn't tag your response with my ID so I didn't get notification of your response.

The control box azimuth reading and the computer azimuth reading share a common 6 volt feed from the rotor potentiometer circuit but each has their own calibration pot. If the control box meter reading is drifting from the computer reading after warm up, I would suspect that one or the other of the calibration pots is the problem. Try rotating both VR1 and VR3 back and forth several times through their complete range immediately after spraying with a contact cleaner. Then recalibrate both after they dry out.

After calibrating, leave the rotor azimuth in a fixed position. With a DVM, note the output voltage of the azimuth reading on the DIN connector of the rotor controller after you have successfully calibrated both pots. If the control box meter reading changes, you know that the problem is in that circuit. If the computer reading drifts after some time, re-check the DIN voltage reading. If that has not changed, then the problem is in your computer controller board, not in the rotor controller box. If it has changed, the problem is in the control box circuit that drives the external DIN connector.

Feel free to post your results after going through this troubleshooting exercise if you still haven't found the problem.

enter image description here

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