Ah, I remember you posting pics of that cab a week or so ago and said it had some sort of DK board in it...figured at the time it was probably Crazy Kong. As to the harness, it uses the Falcon pinout, definitely not a DK style harness. It won't use any crazy voltages, just +5 and +12. There's 2 things you could do. You could just gut the wiring, JAMMA-tize it and build a JAMMA to Falcon adapter, or just get a new 18/36 edge connector and re-wire using the Falcon pinout. Here's a link to several Crazy Kong pinouts, you'll want the 2nd one that says "Falcon 1982" (even though it's 1981):
http://www.arcade-museum.com/pinouts-game/7430.html
Also note, there's 2 edge connectors on the board, and they're oriented 180 degrees from each other, so make sure you plug into the right one with the right orientation. The easiest way to tell is by looking for the end with ground. There's 3 on one side of the board and 4 on the other all tied together, so make sure you orient the edge connector so the ground is on the right end.