PC2Jamma question

[dimmuborgir]

This topic was on Ultimarc.com but it didn't get any answer so I try it here since I also have a main interest in it:

>I've got a dedicated neo-geo mvs 4 slot cab. I'd like to get a jpac and use it with my old pc to play some other games. I think I get most of it, my one concern is the power supply. What do I disconnect to leave power to the monitor on but off to the rest of the cab? Are there any other potenial problems that I might have? Thanks!

I guess the guy (and I) was a little worried after reading this on Ultimarc:

>It is usually preferable to remove any power supply which is fitted inside a JAMMA cabinet, leaving only the monitor powered. With no game logic board to provide a load, most cabinet power supplies would not work anyway. Also keeping 12 volts away from the J-PAC will eliminate the risk of damage in the event that the JAMMA connector is ever plugged in backwards. Another alternative is to unplug the AC supply to the power supply. Ensure that doing this does not also disconnect the ground!

Anyone?

Thanks

CC

[AndyWarne]

Disconnecting the power supply is not mandatory but it is a good idea for the reasons mentioned. By "power supply" I mean the low-voltage supply to the game board. This is normally a metal box with an AC input and a multipole connector carrying the low voltages to the JAMMA harness. If this is the layout then simply unplugging the AC input to the power supply box will disable it.
On some cabs, all the power is inside one integrated unit, including the monitor power and isolating transformer, if there is one. In this case it's not so easy.
In these cases, it might be easier to leave the power supply enabled, but if you do so, make sure you never plug in the J-PAC backwards. The JAMMA connector should be keyed but often is not! Even worse, I have seen a lot of JAMMA connectors that were fitted to the harness backwards, ie the markings on the connector indicating pin 1 were at the wrong end.

Andy