Yaesu rotator g5500dc not responding

SatNOGS Hardware
1

Hello everyone,

We’re experiencing a problem with the Yaesu G5500DC rotator, specifically with the elevation control. Initially, the system was functioning perfectly, but now the elevation position indicator has stopped responding, which is affecting our satellite monitoring operations. Here’s the sequence of events and troubleshooting steps we’ve taken so far:

  1. Initial Setup: The rotator was working correctly, with both the azimuth and elevation motors rotating, and the position indicators on the controller responding accurately.
  2. First Sign of Issue: The elevation meter on the controller began randomly bouncing to 0 degrees and then back to the correct position.
  3. Complete Drop in Elevation Meter: Eventually, the controller elevation meter dropped to 0 degrees and stopped moving altogether (the motor rotation still working fine)
  4. Attempted Adjustment: We adjusted the ADJ potentiometer on the back of the controller. While doing this, we found that the connection to PIN 3 was open.
  5. Re-soldering: We re-soldered the elevation pin and tested all connections. We confirmed connectivity across all points, and there were no short circuits between pins.
  6. Controller Start-Up: After re-soldering, the elevation meter could return to the 90-degree (default) position when powering on the motor controller.
  7. Current Status: Although the motor operates correctly when pressing the up and down controls, the elevation meter no longer provides feedback on the motor’s rotation.
  8. Voltage Testing: We measured the voltage between PIN 1-3. For azimuth control, the voltage fluctuates as expected when the motor is in motion. However, for elevation control, the voltage remains constant at 5.08V, indicating no change with motor rotation.

The elevation’s lack of feedback is preventing our custom software from interfacing properly, as the PC cannot update the rotator’s elevation position, though azimuth control works fine. For interface hardware, we’re using the ST2-USB by Fox Delta.

If anyone has encountered a similar issue or has suggestions for further troubleshooting, we’d greatly appreciate your input!

2

The usual culprit is where you least want it to be, the pot inside the rotator.
You should disconnect the controller and measure resistance to the rotator, if this is open circuit you either have a broken connection in the cabling or more common it is the pot that has died.