6 buttons in opt for 750 elf jammer

[Tumuchfun8487]

Hello,  New to the DIY arcade.
Built a 60 in 1 counter top arcade with no issues.

Now on my second  DIY arcade with 56 pin harness and a 750 n 1 elf Jammer.    Directions state to not hook up pin 27 which is a ground and 28 pin however that's what the jumper grounds are connected to.   Game boots up no problem and joy stick 1 works ok, along with the test switch button but none of the 6 buttons work on player 1 or 2.  I'm sure it's a ground issue but didn't know if anyone has experienced that or resolved the issue.

Would appreciate any suggestions.

[PL1]

Now on my second  DIY arcade with 56 pin harness and a 750 n 1 elf Jammer.    Directions state to not hook up pin 27 which is a ground and 28 pin however that's what the jumper grounds are connected to.   Game boots up no problem and joy stick 1 works ok, along with the test switch button but none of the 6 buttons work on player 1 or 2.  I'm sure it's a ground issue but didn't know if anyone has experienced that or resolved the issue.

The Game Elf "CHAMMA" (Chinese JAMMA) harness is similar to a standard JAMMA harness, but there are at least two pins (27 and e) that are different between a standard JAMMA pinout (grounds) and the Game Elf. (button 6 inputs)
- You don't want pins 27 and 28 connected to each other since that would be like pressing P1B6 all the time.  Same for pins e and f --> P2B6 always pressed.
- If your harness' daisy chain ground wires are on pins 27 and e, you'll need to move them to the correct ground pins.

Pins 28 and f should be the daisy-chain grounds for your buttons.  Does your manual show something else on those pins?
- When you press a button, the COM (Common) tab of the microswitch makes contact with the NO (Normally Open) tab.
- For example, when you press P1B3, Ground from pin 28 or pin f goes in through the P1B3 microswitch COM tab and out through the NO tab to pin 24.

Check the manual that came with your system to see what other differences there might be between your system and a standard JAMMA harness.

Standard JAMMA pinout:


Typical CHAMMA pinout:



Scott

[Tumuchfun8487]

Thank you.  Everything seems to be working now after going through the ground connections and making sure they were seated properly.

So to get the 6 button  to work for P1 and P2, Do I just use a different ground so those buttons work because the manual says not to use pin 27 grounds but the switches only work with a ground.