Again, tried various things. Nothing seemed to be working. Undid the couplers, redid the couplers, nothing. Swapped which was which nothing. Tried setting the speed to the “right” setting. Nothing.
Set the speed to 10 steps a minute (I think, not sure what the unit is, I sent M92 z10). Nothi… Wait, what’s that clicking? They’re turning crazy slow. But, they’re turning. I’ll have to check to see if I can locate the potentiometer for adjusting the voltages.
Winning.