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I'm working on a project that involves stepper motors, and I'm mainly using DRV8825 stepper drivers. At the moment, it seems like only one of my drivers actually gives the motors any current. The others usually return 0s when I measure their VREFs. One returns a value but still can't pull the motors. After checking all of my DRV8825s and finding only two returned VREFs, I checked my A4988s and none of them gave anything (aside from power supply voltage when measuring different pins). Is there a way I can figure out whether my stepper drivers are actually fried? I have a suspicion that maybe the potentiometers on the drivers are thrown off or there's some other issue I can't place. I'm happy to give more information if that can help to figure out what's going on here. Thank you!

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Most surefire way to tell if your drivers work is to wire them up CORRECTLY and try them out. You should not be frying them if you have the correct setup (including current limit) for your conditions. That said, conditions include your heat sink install and the environmental temperature.

The usual gotchas:

  • Note that DRV8825 and A4988s may have different pin locations so be sure to orient them correctly (check their EN pin location) if using a shield.
  • Also note that the gains from the voltage to the current limits will be different for the different model #s. Be sure to use an appropriately sized screw driver and attach the meter to the screw driver as you turn to adjust the current limit.

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