Alright, so after spending the day trying to fix this with Graeme on Skype, we seem to have found the source of the problem.


I have connected all screens to the star point. I've taken the VFD out of the box, power is separate, it's completely diconnected from the control box, and still, no improvements.


Turns out disconnecting the PC solves the issue. So it seems like there is a grounding problem with the BOB. As JAZZ said, it's a cheap chinese BOB, so I might have to change it.


Quote Originally Posted by Clive S View Post
edit: Is that a plastic control box? have you mounted everything on to a backplane (ie metal plate) I think one of your main problems will incorrect grounding
Fiber glass cabinet. Fireproof plate in the back. No metal.


Quote Originally Posted by JAZZCNC View Post
Like Cheap nasty BOB.!!!!!
Jee JAZZ, you don't like them.. :D !


Quote Originally Posted by JAZZCNC View Post
One last thing you haven't earthed the PC case to control box have you.? If so remove.
Nope, not intentionally, but apparently it is through the BOB.


One thing to note. When there is no power to the control cabinet, but the PC is plugged and turned on, the BOB receives 5V, but the 5VDC PSU led turns on, apparently because it receives power through the BOB ! Weird...