Motor Driver Madness

  • So I've been running couple of printers with Duets for a while now (years) and I just had my converted FT5 (an XY variant) wig out on me. I was 97% of the way through a 5 day print when one of the stepper motors started acting like it was wired incorrectly, making grinding type noises and moving strangely.

    I thought maybe one of the wires to the motor was frayed or something so I ran a new set in through the harness. Same problem.
    I then ran a separate set of wires outside the machine from the board to the motor. Same problem.
    I had another new stepper motor lying around, so I ran the new wires to it and ... same problem.

    Did one of the stepper drivers die on this thing? I can't think of anything else it could be at this point.

  • Have you run an M122 command to get a diagnostic report after it's shown the problem?
    Are there any error messages?

  • administrators

    It sounds to me like a partially-failed driver. Try using M584 to swap that output with another one, also swap which connectors the corresponding motor cables are plugged into, and see if the problem moves to the other motor.

  • Update:

    I had been trying to save the print, but eventually just gave up and rebooted the printer this morning. Guess what.. It's working fine.

    Is it possible that the driver overheated?

  • administrators

    Which Duet is it, and which firmware are you running?

    • Most firmware versions will report an over-temperature warning well before the drivers reach the point at which they shut down due to overheating. Please check that you are on firmware 2.02 (or one of the 2.03 betas).
    • The Duet WiFi/Ethernet is unlikely to overheat unless you run it at 2.0A or more without fan cooling. The Duet Maestro needs fan cooling at lower currents, especially above 1.0A.

    It's not impossible that you have an unusual stepper driver fault that only occurs at higher temperatures (but before the warning kicks in). But a more likely explanation is a poor crimp connection on the stepper motor cable.

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