I have a Taz 6 that is very depressed and having funny Z issues.
It does a fine job moving around in all axis via the manual on-screen menu and it can auto home with out a problem.
But whenever a print is started, the nozzle crashes into the wiper on the first G1 Z1 command. It cannot stop from pushing lower and I only have choice to manually shut it off.
Once I turn it back on, the Z motors are stuck and stutter if I try to move it from the menu.
When I turn it off again, manually move the motors back up, then turn it on again, the Z motors are then again functional from the menu.
Really not sure what is going on here.