I bouth my xcarve almos t two years ago, many things keep me from using it, and working on it, i assembled it and asI developed the firstthings to carve in it, and as I tested the gcodes produced by fusion360, once it simply wentall the way down, breaking the bit, since then, whenever I try to use it, the z axis has been troublesome, I already changed the whole wiring for the stepper motor, have checked the tension on the belt, andtodañy i try to use it and again it will not move, themottor will simply buzz, but it will not move it, I really am considering giving up on the machine.
Did you check to see if the set screw in the pulley is tight and not slipping? If it is tight I would take the belt off and and see if the pulley moves then. it could be a bent rod. A video of what it is doing my be helpful.