I have a CNC desktop engraver.(Chinese)
Running it on a desktop with Win XP, no other software on computer.
Running Mach3 software.
Page up sends the spindle down, page down sends the spindle up.
Machine leaves an underscore across the plate being engraved.
Can anyone offer any advice about possible causes?
Any assistance would be gratefully accepted.
Newbie from Brisbane

Within Mach3 - Config / Ports and Pins / Motor Outputs - change the 'Dir Low Active' state for your Z axis (this reverses the direction of the stepper motor).

Tweakie.