Accidental victories
Today I found I had a stuck stepper motor, wouldn't turn when plugged in, but wouldn't even turn when disconnected.
I haven't dealt with steppers before, and the internet didn't have an immediate answer. It did tell me how they work which was useful when I pulled it apart.
There are only a few pieces within, and everything seemed to be in order. Except the rotor just wouldn't turn without a lot of force. So I carefully used my pocket knife to make sure each coil in the stator was fully separated, not touching its neighbour or anything.
And that seemed to fix it! Reassembled, plugged back in and now it's working as expected. Perhaps a bit lucky but I'll take it.