Quote Originally Posted by JAZZCNC View Post
This won't be copied software or Mach3 fault. It will be one of 5 things.
#1 Mechanical issue so slipping coupler or something.
#2 Electrical noise from spindle affecting signals.
#3 Incorrect setup of Steps per milimeter
#4 Pulse signal is set wrong in drive so changing on wrong side so losing 1 step on every directiuon change.
#5 Low power parallel port voltage so not enough voltage differential between high and low signal causing lost steps.

My suggestion is first check all mechanical connections and wire connections. Then identify if noise by running G-code in air without spindle running. Measure starting height and check when finished.
If ok then check the Active edge set in the drive.
I have already check all the couplings, they seem to be good. How do i check if pulse signal is set wrong in drive? Yes there is some noise while running in air, some strange noise like clicking. Starting point is not the same, its like 3-4 mm deeper when the program finished. What does active edge means, what is it used for?
Thanks for your help.