VFD interference problem

[eurikain]

Going to sound obvious but have you tried another parallel port cable.? Also you are using a proper straight thru cable not some Old printer cable.?

I haven't. I have a PCI PP card that I will try to install and use on Thursday, this might prevent the ground loop, who knows :)

[Clive S]

I haven't. I have a PCI PP card that I will try to install and use on Thursday, this might prevent the ground loop, who knows :)

It is important as others have said to try a different pp cable or at least check the continuity from pin one to pin one etc at both ends of the cable.