My cut motor quit mid project. I've replaced it with a new one. Now, as soon as I select a project I get a z axis stall. I tested the board sensors at "0" and "8" on the control panel. X and Y are fine. As soon as I hit the test key for z I get the z axis stall message. I tried to check the cut motor. When I try to test, I get the same z axis stall message. ????