Tell me why this won't work... printer switch-> JAMMA switch

[Well Fed Games]

So I want to be switching my jammas but I am not wanting to be spending my monies. Any thoughts on whether an old style printer switch (one input, two knob-switchable outputs) could be re-purposed as a JAMMA switcher? Still getting my head around JAMMA wiring but I figured one of you could tell me if I was barking up the wrong tree. 

[MonMotha]

It probably will work, but you won't want to run the power lines through it.  Those switches and the tiny wire used can't take nearly the current your average classic arcade board draws.  You could use one spare wire as a relay pilot to switch the power if you want or just leave both boards powered at all times.

You may also want to note that many of them don't switch all 25 wires.  Several of the wires on the PC parallel port are just ground (IIRC, the last , so some of the switches just commoned all those up.

[Well Fed Games]

Thanks. I was wondering about power. I'll do some more research on the pinouts and stuff!

[MonMotha]

Switches come in both "make before break" and "break before make" configurations.  Both are useful in certain applications.  It's possible he wasn't completely blowing smoke.

Regardless, a relatively brief moment of connecting both printers together like that is very unlikely to cause problems.  Heck, a lot of those old PC designs could withstand indefinite shorts to VCC/GND on all of their IO lines.  IIRC, IBM specified either a 5 minute or indefinite short to 120VAC on their RS-232 ports (don't try this at home!).