Power supply ground question.

[Stobe]

I searched the board, and found an answer, but I wanted to double check first.

I'm getting ready to hook up my JPAC to my new jamma cab.  I read Ultimarc's installation suggestions, and I have a question about the grounding:

I removed the leads going from the power supply's -5V +5V and 12V that ran to the jamma connector.  Still plugged into the PS are AC, AC2, FG, and all the grounds coming from the harness (these grounds from the harness need to go somewhere, right?)

When checking all my grounds, my monitor frame , FG terminal on my PS, and AC ground are all the same.  But they have no connection to the grounds running from the DC PS to the jamma harness.  I've read that if you have interferance on your monitor, you should run a jumper from FG to GND.  I have not hooked up my machine yet, so I cannot vouch for any interferance.  But should I jump these together anyhow?

Also, does the jamma harness have to be connected to something (JPAC) for the grounds to be connected to the button/joystick commons?  When I quickly checked, they didn't seem to have a connection.

Thanks for any/all help.  I wanna fire this bad boy up!

-Stobe

[pcb]

I'm not familiar with the J-PAC, but generally you need a board or something with a common ground plugged into the JAMMA harness for the grounds to all connect.

Most folks steal one ground from the harness for the CP, and another for the coin-door.