Microswitch Ground
- Microswitches -
What's the common for?

FAQ - Where do I hook-up the wire for the common terminals of my microswitches?

With an influx of newbies to the collecting world come some of the most basic questions that we all take for granted.

The answer should be self-evident on my Help Page here:

Basically, you run a ground line from your edge connector ground & loop all the commons into it & then back to your starting point, attaching it to an adjacent ground position in the edge connector, so that if one connection to ground fails the other will keep the integrity of the ground circuit. You can also terminate your loop for each line that you run since it would be obvious as to the location of an open ground line by the area in which your switches do not function. For example, I always run a separate ground line for each of the following areas...
in the video bundle, the coin door bundle, player 1 bundle, player 2 bundle and for the speaker...so any switches used for player 1 controls are in a loop of their own from the first switch to the last switch & back to the start point on the first switch. If any one ground loop breaks it will still make contact in the opposite direction & if all switches fail in that loop I know it is between my first switch & the edge connector... the only lone common ground wire & easily identified by the junction of 3 black ground wires - in from PCB, start of ground loop & the closing ground loop wire. A *lasso* arrangement, so to speak.

The other question that usually accompanies this one is, "What size wire should I use to hook them up?"

Wiring other than the 18ga power conductors should be done with 20ga whenever possible & 22ga when you just don't have the 20ga that you need. Anything smaller than that is just a pain to work with & maintain. It might be fine for your thermostat wire in the attic of your home, or in the phone lines in your wall or any other app where the wiring is not exposed to us humans & has screw terminals for termination of that smaller wire, but right out here in the real world where we have to come in contact with this wire & utilize it for crimping, soldering or even the el cheapo push-in connectors... it just doesn't wash :-( Cabs used to swap in & out multiple PCBs don't stand a chance with the smaller gauge wires considering the amount of times they must be handled. The only thing I could think of that could be worse, would be using solid wire in place of stranded wire in game use :-( Now that's not asking for trouble, it's begging for trouble :-()

Replacement Jamma harnesses in their infancy tried to skimp on wire gauges & brought barrels of grief to buyers & techs alike. Wires pulling right out of the connector housing.... overheating power terminals... burning edge pads... having to crank the switcher open to full bore in order to bus the 5 volts to the components on the PCB... intermittent connections..... open connections where the insulation actually fooled you into believing that the wire was still connected by hanging onto the terminal saddle... and a parcel of other misadventures along the way to destinations via intra-cabinet break connectors.... CP, coin door, video & etc. To add ease to the demise of a connection, quite often the paws of even this *Big Bear* would sometimes snag a wire and yank it from it's home while removing or installing some component :-(