recently I have a Lerdge X to which I had to put two steppers in parallel on z.Initially I seemed to be fine. Now, however, that I wanted to calibrate z is crazy: initially it goes and then emits a strong buzz and does not move. I do not understand where the problem may be. There are no particular messages on the panel. Only problem is that the cables have soldered waiting for me to arrive the stepper splitter Lerdge, but it is the same thing I think ...The behavior is this: the axes x and y go normally, z instead initially works and then emits a buzz and does not move that minimally downwards, as by inertia.