Sega-Naomi

Hello. I'm trying to get my Virtua Fighter 2 pcb working in my Egret II cab via a Model 2 to Jamma harness, but I can't get any of the buttons to work. The video works fine, but for some reason not a single button will work. Its not even a question of maybe the wires being in the wrong place, not even one button will register no matter what pins are connected where. I'm connecting to the 25 pin, 24 bit connector on the filterboard. Could there be a ground I'm missing on the convertor? I'm completely lost. For the convertor, all I basically did was connect the wires to the proper place on a Jamma fingerboard, and hook them up to the appropriate spots on the 25 pin. Is there something I'm forgetting?

use a ground wire from the PSU, on the one of the 25pin connector pins for example pin 7

Thanks Andy. Actually, running the wire from ground to one of the pins on the 25 pin connector didn't work. I was able to get the buttons working by running a wire from my ground loop on my control panel to a different ground (I used the side of my PSU.) A few problems with this though...since the service and test buttons aren't connected to this particular ground loop (the one that connects the buttons and joysticks), those two buttons don't work. I'm confused as to why I need the extra ground at all, because all of my Jamma games work properly without it. The seocnd problem is that some of the pins on the 25 pin connector aren't even connected, yet the buttons are working anyway...for example pin 20 is 2P Guard - its not connected, but its still working with one of my buttons. Also, pins 1 and 2 are for the coins - they are connected, but none of the buttons can be used to insert coins. I'm afraid there may be something else I'm missing.

Ok, it looks like the problem was that pins 27 & 28 on the Jamma fingerboard weren/t grounded. Is it safe to use the ground on pins 1 & 2 for this, or should I use a different ground?

if your using a JAMMA fingerboard, your grounds should be common anyways so should be okay to use any ground pin

All GND should be common as Meg said.

Thanks again for the help. Another quick question...anyone know where I can find the 25 pin connectors for Model 2/3 harnesses? All I have are ten pins, so I've had to double some up for the 25 pin connectors on the filterboards.

You'd have to goto a JST distrubtion company, the 25pin housings are not common.