Well I figured something like a loose cable would cause the signal to cut flicker off and on rapidly, where something like a cap could be affected by radio frequencies and cause bizarre pulses and fluctuations...

(I only pretend to have any idea what I'm talking about when it comes to this sort of thing) :beige:

anyway, the problem fixed itself almost randomly when I adjusted the screen position later in the day. I'll post again if the problem returns.