if you are having issues, it could be because of your parallel port
i have been using mach3 on a diy lathe since a year. But mach never gave me an unwanted move. Yes, once there was some problem in the leads of an axis but it was a bad DIR pin on the parallel port. now i keep the things on add on pci parallel cards and if i face an issue i put another one first of all.
they are really cheap (5$ each) so i keep two or three in spare.
The best thing is to keep a backup of the xml file in your mach3 folder. If you are having a new problem, try restoring the older settings to make sure that things work like before again and then redo the changes you want.
I have seen some people using mach on machines having 12kw spindles and 1.5 kw servos so you should not be worrried about it.
One suggestion from me- if you are wiring the inputs outputs first time, use an isolated bob.
(on board port is always priceless)
jasminder singh
It is better to die for something than to live for nothing.