Home Jamma on the Cheap

Living in Japan has it's advantages. The girls are cute, the cars are cool, and the games come out here first as a rule. Occasionally though, you run into problems. I finally obtained a Raiden Fighters arcade board from the states and desperately wanted to play it. A trip to Akihabara, I thought, should sort me out right quick. Such was sadly not the case, however, as you'll see. Read on for a short story and a guide to making a quick and dirty jamma adaptor for home use.

As you may or may not recall, the Arcade Primer showed that the basic parts of an arcade system were fairly few and simple. All I needed to make this system run was a power supply, a display device, and some controls.
[Jamma Harness Schematic]
Display Device: This was easy. I wired the five video signals (red, green, blue, sync and ground) into my custom pinout. I planned on using an XRGB2 unit to display the game on a VGA monitor, and already had the cables ready for a 9-pin plug.

JAMMA Harness: You'd think that this kind of part, necessary for almost all arcade games produced after 1988, would be common in Akihabara. No joy - I had to buy a wiring adaptor from MAK which included all of the wires I needed, and cut out the bits I didn't need.

Power Supply: My trip to Akihabara proved that even the great Try Inc. couldn't supply me with parts - they had neither power supplies nor harnesses. I decided on a computer power supply; they were cheap, small, easily available and had the necessary voltages (five and twelve volts). Since no games I have use negative-five volts, I didn't bother hooking them up.

Controls: I've found that NEO GEO controllers are versatile beasts, from slaying savage hoards to slicing bread. I ran the player controls to a NEO GEO controller port which allowed me to use any NEO controller.

It may seem daunting, but there's surprisingly little to it once you've gotten the parts together and banged your head on them a few times. Simply connect the dots! If you'll have a look at a JAMMA harness you'll see the connections are clearly understandable. Connect, for example, the player 1 controls to the player one NEO connector. Start connects to Start, Right to Right, button 3 to NEO C button, etcetera.
[Jamma Harness Schematic]
As you can see, there's nothing to it. If you couldn't connect the dots using the different diagrams before, beat yourself for being stupid. If you can't figure it all out from THIS diagram, there's simply no hope for you and you should stop reading this and step into traffic. >=)

NEO GEO controller port
JAMMA harness
Video Pinout
PC Power

[A picture of the real harness]

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