What would cause ripple interference seen on on a display whereby the computer is attached to it via VGA?
By ripple interference I mean that the edges ripple and the display flickers. It is occasional and intermittent and it may occur for a few seconds to a little longer.
My set up - the problem is seen with a 2010 17" MacBookPro attached to a KVM switch via a DisplayPort to VGA adapter. 2 other machines are attached to the KVM switch.
The problem has only begun recently, up until then this arrangement worked very well. The other 2 machines (Windows 7 and XP-based) don't show this problem when they are using the display.
I don't want answers advising to move to a HDMI or DVI based KVM switch for 3 reasons: 1) because I am reluctant to make additional purchases and 2) this arrangement has worked well for at least 6 months now and 3) One of the machines only supports VGA.
So to recap, what would cause interference on a VGA signal? Could it be a hardware issue?