What I mean that all seems ok, is in comparison with the last state of the machine when the motors were going nuts and the limits were switching erratically.
The bob is not grounded by any individual cable. I assumed that via the usb cable, a ground is provided, which goes to the pc case, and then to the mains.
I did not measure the ground from the mains, but when I touch it, it gives a tingling sensation, like is has some voltage going through it. This is the mains earth as it comes into the property.

The bright side is that it.s all better than before, so I.m still happy, even if, righfully so, Clive disagrees with my so called ˇˇall okˇˇ opinion. I.ll rephrase that. All better than before.