I have recently installed my steppers (1.8, 270oz nema 23s) into my cnc machine, with the much talked about TB6560 bob (24v+ power supply, running with licensed mach 3). Everything runs fine on all axes/board runs nicely, with the exception of the terrible screeching coming from the steppers when powered. Even on its lowest power setting, 1/16th steps, the motors make a high pitched screech (full steps becomes unbearable).

I am still new to cnc so please bear with me. I am suspecting my wires and board aren't grounded/shielded properly? I've tried step low active, but the steppers stall on signaling; no movement (I've not installed my e-stop, or limit switches yet). Debouncing I honestly don't know what value to enter (I've ranged from 1000 to 2000 to no effect).

I've read that some have used a lower 12v power supply to fix the problem. There isn't hum coming from the motors when idling, and they don't even get very warm when running (which is nice), so I know the motors are working fine. I am drawing a blank and hoping for some advice from someone who has dealt/ solved this. Thank You (It may also be that I have my board/ power supply on the floor, second level and it is receiving from the wires running around it, I can hear the pulse when hooking up audio equipment?)