The RIGHT way to approach Arcade Wiring (for n00bs like Me)

So after doing pretty much all the dumbest things I could have (short of perhaps blowing up the control panel with dynamite) I now have this simple tutorial to show what you should do and exactly what you need to do to get the most out of your Ultimarc purchase.

Everything you need
If you're going to buy parts, make sure to get everything you need before starting. It's tempting to just want to dive in there but believe me, doing this the right way makes everything 100x simpler. To begin with, you need a PCP such as the Mini-PAC. I chose the Mini-PAC Opti. with harness. This allows me joystick+6 buttons per player, 4 utility buttons, l/r mouse, trackball (x,y), and spinner. Unless you're doing a 4-player board, I don't see any point in going the I-PAC/Opti-PAC combined route (it's very much the same effect for way more money). I also highly recommend you buy the "wiring kit" and the mounting feet for the Mini-PAC as long as you're placing your order there anyways. The wiring kit comes with extension wire for every color used by the harness (plus extra black since that's used for ground). It also includes 100 quick-disconnect connectors and a crimper. And, make sure the buttons you buy have the same 1/4" size. if everything's the same size, tis way simpler.


Other than that, you really only need a staplegun, tie wraps, needlenose, wire stripper, male quick disconnects (I'm not 100% clear what you get with that wiring kit), and some M-M-F Quick Disconnect splitters. Radioshack's splitters came in a variety pack which was handy.


Basic Wiring theory
By default, you want each button's switch in the middle of a loop going from the PCP to the button (which is open by default) and back to the PCP's ground. Then, pressing the button flips the switch to complete the circuit. Doing it backwards would have the key down all the time by default, releasing it only when you hit the button. About 1/2 way through my first attempt I realized that the switches have a mini diagram engraved into their side to show you what the two prongs mean that are next to one another. You want to always use the prong that matches up to the dot in the diagram which DOESN'T have a line back to the center dot. For joysticks, you may need to unscrew the switch from the stick to flip it over so you can see its diagram and confirm which prong to use for the harness connections. The ground loop goes through the other prong on top of the switch opposite its button.

I made this little diagram to help explain it visually. The diagram displays three different buttons, two of which do the same thing.



1) Study the wiring diagram and read their instructions carefully.


2.) Tie-Wrap the harness wires to match the diagram so you can quickly analyze which group/color matches up with which button as labeled on the diagram.

3.) Work your way down the diagram, connecting positive (harness) cables to match with the diagram. At some point in this step, you will come across a switch that is too far for the harness to reach. All you need to do is crimp a male quick-disconnect on some new wire (ideally wire which matches the wire that's too short). Plug this into that harness quick-disconnect. Extend enough wire to easily reach the destination and crimp a female quick-disconnect on that end. Plug it on the correct prong.


4.) Connect the ground quick-disconnects in a loop around the CP, making sure to reach the ground on every switch (switches won't work without it so it's a common reason why one of your buttons won't work later). Just as in step 3, use quick disconnects and spare wire to make sure the grounds reach every switch. Note that in cases where you have only a few buttons far away from the previous ground plug, you can branch out using a quick-disconnect splitter. Send a tributary off to that first button and crimp two wires per quick-disconnect (just like Ultimarc did) and you can have it stretch out without having to make a return trip back after hitting those stray buttons.

5.) I had an Ultimarc Trackball too. This came with its own red/gold/green/black wiring leads which you can disconnect and set aside. To connect the trackball, first be sure the power end is plugged into the Mini-PAC (near where the main harness goes in). Then try to track where the appropriate wires from the diagram go. I got confused by looking only at the colors and assumed the power was purely power (instead it branches to feed all three of the other ends). Simply plug in the X (horizontal) and Y (vertical) axes' molex connectors on the pins of the trackball. At this point you can test it to see how it moves the mouse around. It is very common for one of the axes to move backwards (for me up went down and vice versa). To correct this, find the wires for that axis and cut/cross the two wires in the middle so that they "cross the streams". This reverses the signals to correct the direction issue.

6.) Any spinner you may have which requires this same kind of connector as the trackball can simply take advantage of the final molex connector. I don't currently have a spinner but the cheap one I've got my eye on is actually USB and won't be using the Mini-PAC.

That's pretty much it! Once you get the hang of crimping the quick-disconnects it's a very simple and straightforward process. And if you mess up, you can always trash the extension wire and redo it without violating your harness.