Oh my god you guys, I am really just beside myself with frustration here.
I've been having the same z axis problem that it sounds like lots of folks are having: works fine with the manual controls on the control panel but grinds on homing and doesn't reach the full z height.
I have calibrated the stepper drivers for the old NEMA 17 motors, downgraded to the motherboard firmware 3.0, edited the xml file to set the z stepsmm to 2560, re-tensioned my z belt and quadruple checked all of my physical connections.
If I manually move the z axis up to the endstop it will run smoothly, and turn off as you'd expect when it hits the stop. X and Y are both fine manually and when homing.
I set the z max rate and homing rate way down many times. Initially I had them at the original values and the axis would half work for a few minutes and then grind, so I turned the values down some. The same situation would arise. Now I've got them both down to 55, and the z axis is still grinding on homing.
Really any suggestions would be most welcome.
