I have an older Novakon NM200 mill that always had some weirdness but nothing I couldn't deal with for home/personal use. But just before Covid really hit the Z axis went completely haywire, swapping stuff around it was clearly a board issue and Novakon isn't great for support. So I decided to redo the controls, going from Mach to Acorn, going to a bigger AC spindle motor/VFD and reconfiguring the cabinet at the same time.
Just got it up and running and I'm very pleased so far, haven't made any chips but everything seems to work just a little better. Electronic/wiring stuff isn't really my thing so it took me longer than someone that has a knack for it but the Acorn documentation is amazingly thorough. And the user interface is also worlds better than mach. I feel cheated not having known about it sooner.
Pics of before/after cabinet, the wire runs could be tidier but I was starting to get impatient.