I am trying to put together a circuit that will make the screen of a VGA monitor go black (controlled by a switch). The idea is to "ground" just the RGB lines so that the monitor does not go into a power down mode. I've tried a simple circuit that just routes the RGB lines through a 4066 quad switch without luck - in the on state, the signals were obviously attenuated. I was thinking about trying a relay, but I don't have very much experience dealing with this kind of circuit. My question is can the RGB lines just be switched to ground, or should there be resistors in there? My guess would be that the off state should actually route the signal to ground through 75Ω resistors, but that really is just a guess (my experience consists entirely of digital circuits and some simple analog ones where impedance wasn't such an issue). If that's the way to go, should the resistors be on both ends (i.e. put a resistor between ground and the RGB lines on both the computer and monitor ends of the line). I would really prefer to keep the whole thing solid state, so if anyone has suggestions along those lines I'd appreciate that too.