Mechanized Attack / JAMMA adapter - sync issue

[MrD]

I got a Mechanized Attack PCB and trying to make a JAMMA adapter for it. Pinout is attached. I was able to test it and the board boots but I can't get it to sync. I've tried two different cabinets with the same result. Other PCBs work fine. I've checked continuity on all wires on the adapter and they look good.

On the pinout there is only Video R/G/B and sync. There isn't a video gnd. So on the JAMMA side, that pin isn't connected to anything. Could that be the issue? If so, what do I connect it to? Just the regular GND on the adapter ?

 

[MrD]

I did a little more research. I bought the board "working" but you know how that goes. Its possible it has an issue. But, it does start up. Plays music. Takes a coin, etc. So that part is working. I've tried it in 2 different cabinets with similar results.

I'm trying this in an Area 51 Site 4 cabinet. It has a Neotec NT2515C monitor. I looked at the wiring diagram of the cabinet and it shows the video signal ground going to Pin 14. (which I hadn't hooked up on my adapter since there wasn't a video ground on the Mech Attack pin out.) I found another wiring diagram for this PCB. It shows CRT GND at Pin 17 on the PCB. (which is the same as all the other GND connections) I tried connecting JAMMA Pin 14 to ground and it still doesn't work. I could almost get it to sync, but not quite. I rechecked continuity on all my adapter jumper wires and it all looks ok.

I think I might be above my pay grade now.

 

[Shinobi 1]

Did You Get This Figured Out Yet ?

 

[MKFan4Life]

If you haven't solved this, have you tried tying Horizontal & Vertical Negative Sync together at the monitor's video connection header? This game probably has Composite Negative or Horizontal Negative sync. (Older games sometimes used Positive Sync, but I doubt yours does.)

I looked up SNK Mechanized Attack but couldn't find that tidbit of info. I've heard many times tying the two together can fix sync issues. Or if they're together, just try either Horizontal Negative connected to the game board's sync wire or Vertical Negative.

As a last resort, try the pins closer to the color and ground connections (the Positive Sync pins). Worth a shot.

 

[hawkeye]

I sent you the wrong picture this is the correct way to hook that up if you do like the first picture I sent it won't stop scrolling.
Didn't have any issues testing the game on a vision pro with the original signal harness.
I had to modify the harness to get it to work on a k 7000.
I did this today.

 

[hawkeye]

This should answer any questions about the signal harness issues on that game