Y Axis upgrade issue

I recently upgraded my Y Axis to the 2 x stepper motor upgrade. since then everything has been fine. However over the last 2 days I have noticed one motor will just stop in the middle of a cut. There is no binding or any indication of resistance, the motor just stops,while the other side continues on until it binds and also stops.

Once I reset or 'Home All' everything works again. I know all my connections are correct and tight and the machine has recently been cleaned and re-greased. I have just upgraded my UCCNC to a refurbished desktop PC but I do not believe that could be the problem.

Has this happened to anyone else or does anyone have an idea what could be causing the problem? Any advice would be gratefully received.

regards,

Sonny