I'm looking to create a VGA fader - I have a projector that takes a VGA
signal from a PC, but I want to be able to fade that signal down to black
between projections, manually using a slider. I know there are production
items out there but they are in the region of upper hundreds and over-spec'd
for what I need. I just need to be able to fade in and out one input.

I cant find, on a brief hunt, the VGA signal spec but I would guess its got
a sync line and 3 AC signals for pixel brightness. I hear it may be ~0.7v
p-p but i dont have that confirmed. Would it be fairly simple to create a
variable gain amp to maintain 1:1 or lower gain to fade the signals to black
without losing sync with the projector (it pops up a blue screen when the
cable is unplugged). Obvioulsly one amp on each analogue line.

Any hints/pointers would be of great help!

J