Grounding Jamma Connection??

[lettuce]

Does anybody know where pin A & 27 (ground/+0V) on the Jamma connection are surpossed to be connected to?. As i found that the other 6 GND pins on the Jamma connection go to ground points on the cab. But pin 'A' (GND) goes to the Player 2 start button on the Control Panel, and  pin '27' (GND)goes to the left microswitch of the player 1 joystick. Is this usual as it seems a bit strange to me, and dont know if these pins are actually grounding out??

[SirPoonga]

http://www.coin.demon.co.uk/jamma.htm

Are they going to the NO part of the switch or the ground part of the switch?

[Rocky]

Grounds are needed in a lot of areas of a video game:

[Stobe]

DC and AC are usually isolated from each other.

I found this to be the case in my JAMMA cab.  All my AC grounds were common, and my DC grounds were all the same, but they were seperated from eacher (AC and DC).

This makes sense to me electronically, but Ultimarc's site instructs you to check continuity between AC ground, FG, monitor frame, CP commons, etc....??

But to answer Lettuce's original question, I would only guess that those GND connections are probably going to the 'common' connections of the microswitchs, and all other microswitches in the CP are daisy chained to those 2 tie points.

If you don't know off hand which connectors are NO and which are Common on your MSs, just check continuity between those two points in question, with all the other common connectors in the CP.

-Stobe

[RayB]

All buttons and joystick switches should be grounded to the same ground on each player side.