Type of Switch

You need an actuator. Mount an appropriate length lever on your A/B switch knob stud and move it with one of these:

Linear Actuators, Linear Motors, Micro motors, Electric Motors

Good luck!

As lynlynch indicated, you already have the switch, what you need is a means of turning the switch (an actuator).

I think the simplest actuator would be a solenoid.

On the other hand, a set of switches with a built-in actuator is called a relay. As I recall, a VGA A/B switch has about five wires that are actually switched (I am not where I can look at one quickly). A 5-pole, double-throw relay replacing the current rotary switch would require soldering about 15 wires, but would result in a much more reliable unit than jerry-rigging an actuator to the existing switch.

Why not wire a solid state relay into the circuit in place of the switch. Move the switch to the sound booth to actuate the relay. Run a pair of wires between the relay and the switch in the sound booth. All you need to know is how much current you are switching. Probably not more than 20A?

He's switching VGA (I presume this means Video Graphics Adapter). As I indicated before, I'm out of town right now, so I can't go out and look at an A/B box for VGA, but I believe I've seen some that only connected 5 of the 15 connections.

In any case, he must switch at least the R,G,and B signals, so he needs at bare minimum a 3PDT or 6PST switch. Current is in the mA range, so that's not a problem, but voltage drop across the switch would be, so I think physical contacts of a true relay would be better than the triacs commonly used in AC Solid State Relays. I haven't seen 3PDT or 6PST SSRs, but did not do a search... If such exist in small packages with very low voltage drop, then that would be ideal.

A typical VGA connector uses 8 signal wires and 5 grounds and two pins are reserved. Three of the signal wires are for monitor ID and are not necessary to display a signal if the signal is compatible with both monitors, one monitor could be left to drive those three pins, or they can be left open or they can be switched if desired. The grounds can (and should) be tied together. that leaves five (or 8) signals to be switched. Pin 9 is +5 volts supplied by the graphics card which can be used to power an AB switch.

A simple means of accomplishing this would be to use two 4066 quad bilateral CMOS switches to switch the 8 signal lines. The beauty of this is that it keeps the switching voltage low and intrinsically safe and the controlling switch can be mounted remotely.

I would add that the on resistance of the 4066 is a function of the power supply voltage, and is typically 80ohms at 15V Vss and 270 ohms at 5V Vss so it might pay to have a separate 15V (well) regulated power supply powering this to keep the signal losses as low as possible.

Maxim makes an improved version that might be more suitable.

oops, I just realized it would take 4 of these chips, along with a 4049 hex inverter so that you could drive half the switches on while the other half were off and vice versa.

Right you are! In fact, about 25 years ago I used 4066's for switching audio signals. Unfortunately, there was a small but perceptible click at switch time, which was unacceptable in the application I was designing (a hearing test).

A single transistor could invert half of the control signals instead of the 4049...

Moog Taurus pedals used 4016's and they ate them like candy I was told by a musician friend of mine. I suggested that replacing them with 4066's might be better but since the unit was an analog synth, the resistance of the switches was apparently an issue. Here is the schematic.