Control board causes interference via USB

[Softfoot]

When I have my I3 Pro C with a GT2560 A+ controller connected to my PC via USB I see lines of interference running up the monitor !!
Its almost like mains hum.

If I power down the printer or unplug the USB it disapears.

I tried removing F2 from the controller but it made no difference (it did stop the controller being powered from the PC which seems a good idea).

The printer and the PC and the LCD monitor are all plugged into the same wall socket.

Any suggestions ??
Could it be a ground loop ??

TIA,
Dave

[Jarda3d]

Use the same 230V outlet for all devices. Check that your home power lines are safety grounded. Check that you are away from RF communication devices or from running microwave oven behind the wall.

[Softfoot]

They are all plugged into the same outlet and are all fully grounded at least as far as the plug is concerned.

A USB isolator solves the problem so I suspect it is a ground loop of some sort.

I note that the mains earth onthe Greeetech supplied PSU is not connected to the case of the PSU or the black ground wires on the 12V output wgich seems a bit odd.

Dave

[Jarda3d]

It could be problem with the mains cable too, try to change it.

Check with multimeter beep test grounding of frame to GND socket, and GND to PE socket.

You need to solve it for safety reasons.