Jamma Harness - Where is Ground for Coin Door wires?

[markrvp]

I've wired up 3 cabinets now with Jamma harnesses.  When I get them, they are already separated into bundles for: power, coin door, speaker, monitor, player 1, player 2, and COIN DOOR.  There is no ground wire in the coin door bundle.  However, the Test and Service switches along with the two switches for the coin mechs all need to be grounded.  I've been just tying a ground wire to the control panel ground. 

I realize that ground is ground, and it's all coming from the power supply anyway, but it bugs me that there is no ground wire in the coin door bundle of wires.  In commercial cabs with Jamma Harnesses, where is the ground wire coming from for the coin door stuff?

[Ken Layton]

One of the black wires from the very end of the Jamma connector. Any one of the wires at position "e", "f", "27", or "28" will do.

Lots of times I've received brand new Jamma harnesses that were not properly bundled so I'd redo them myself. Sometimes we'd buy a used machine and I'd open it up to inspect the wiring to see if it was wired correctly & neatly. Most of the time it would be a mess and you'd hear me cussing my head off because whoever wired it before we got it did a piss-poor job of it or just plain didn't know what they were doing!

[markrvp]

Thanks, Ken. 

Just to make sure I understand correctly - A, B, 1, & 2 all go to the ground terminal on the switching power supply, right? 

Then that leaves Ae, Af, 27, & 28 that go to both players and the coin door?

[Ken Layton]

Yes

[Q*Bert_OP]

I know that Happ's harnesses are like that...they also really suck because I've had 2 of them come with bad pins out of the bag...