The USB B connector (printer cable) is loose. The cable fits tightly in the connector, but will disconnect at random especially if the cable is bumped. Short of pulling the controller apart, does anyone have suggestions? I have replaced the cable that came with the MK2 last spring. Disconnects can happen even with the vacuum not attached or running. No other power tools in use on that circuit.
@Graham , I had similar issues stopping disconnecting etc. I did the ground wire on the Vac hose but latter noticed the machine can be sensitive to anything else running on the same ac circuit. I think to solve it completely maybe an isolation transformer would be of great assistance. If you replaced the usb cable make sure you use one with ferrites to eliminate interference. CLICK
I was having this same issue when I started. My computer is just outside my shop to keep it out of the dusty environment. I was using a good 25" USB cable running above the suspended ceiling but kept dropping the connection . I solved this by replacing the cable with a 20’ shielded USB cable. That was several month ago and have not lost the connection since. Might be worth a try.