Quote Originally Posted by Web Goblin View Post
Did you swap the good original IC to the positions of the faulty ones to see if the drives ran ok one at a time? You could also have faulty driver chips. Or you could stick one of the new ics in the known good axis position to check it out.
Agree with Web Goblin swap things around to eliminate things.! . . . .After that then don't waste any more time on them Crappy Allegro A3977 chips and All-in-one boards.
You'll have this problem all the time unless you run them well below there rated currents/volts.
You can get decent 50V lead shine copies for not lot of money and while not the best drives in world they are still miles better and far more reliable. So cut your loses and save your self the frustration.!!