I have a wonky Y axis( Not X, Zor A).
When the machine is idle the Y stepper will vibrate  back and forth ( ie CW to CCW to CW) about a step or two with a frequency of about 2-4 times per second.
If I jog the axis while this phenomena happens the axis is weak and will skip steps. Programs run recently had missed steps in the machined part.
When I click  RESET to electronically disconnect the controller from the PC the vibrating stops. When I click RESET again to re-engage the pairing the vibrating is absent and hard to reproduce.

My  hardware is an old XP box, a Xylotex XS3525/8S-4 and Homan break out board

I am requesting phone support find out if it is the PC hardware, mach3, or the controller assembly?
zanyantiks@gmail.com