I bought a kit off ebay, that included 3 used stepper motors and a 3-axis driver. On the driver board the company name is Mechatronics, but I can't find a manufacturer website anywhere. I bench tested everything, and it seemed to work ok, but now after installing the motors on my cnc, the z-axis doesn't work. When I connect coil A, and turn on my power supply I hear a squeal, and then the fuse blows. I can connect the same motor to the other axis and it works fine, so I have determined the problem must be with the board. Has anyone had experience with these boards or can suggest a component to check?