Motor is acting strange


I just updated the software and firmware on my 2.6 and now the port motor will not work. I have recalibrated the ESCs and both starboard and vertical motors are working normally, but the port motor is not. I also reset the ESC to factory conditions and reprogrammed it from the ground up. When I turn on the ROV the motor starts shaking back and forth like it can’t decide which way to spin. Once I actually tell the motor to move it just jitters in place until I poke it at which point it just makes a few jittery rotations and then stops again. Any idea what could be the cause?

Update: I have updated the software to the latest version, updated the firmware and replaced the ESC, none of which have solved the problem. In addition the ESC no longer beeps when I attempt to calibrate the motor.


Hi @carignansam:

The symptoms you describe sound like one of the leads to the motor is not connected- either a motor lead has broken, or for some reason the controller board is not making contact with all three motor wires.

I would start debugging this by taking an ohmmeter, and, with the controller board disconnected, making sure that there is continuity between all three motor wires when measured at the DB-25 connector- the resistance of the motor windings is a fraction of an ohm, so measuring between any two of the wires will look like nearly a short circuit.

One other thing you can try, if you think there’s an issue with the processor on the controller board, is to pull the servo cable for the bad ESC off of the controller board, and plug in a servo tester. If the motor spins properly using the servo tester, but not when the servo cable is plugged into the controller board, then there might be an issue with the controller board.

Let us know how things progress.