Help... jamma pinout

c_mon · Post by **c_mon** » Sun Sep 16, 2007 3:45 pm

I recently found a pinout for jamma pcb.

Link: www.gameland.gr/geoanas/realarcade.htm

Can someone explain me what does '-5V', 'KEY', and 'Lock out coil' mean?

Look to the standard jamma pinout. Help would be very appreciated...

Post by **bicostp** » Sun Sep 16, 2007 3:56 pm

-5v is just that, negative 5 volts.

I think key is either a missing pad or a lump in the middle of the connector so you don't plug it in backwards.

Apparently the lock out coil connection is used to automatically reject coins inserted while the cabinet is off, but it isn't used much.

c_mon · Post by **c_mon** » Sun Sep 16, 2007 4:07 pm

How do you get negative 5 volts? I've been working with only positive 5 volts so far. Where will you find -5Volts? Will it come from 7805IC or so? Will I have to reverse +5 Volts in some way? If you know can you explain?

Kyo · Post by **Kyo** » Tue Sep 18, 2007 9:11 am

aren't those coming OUT of the device you plug into the screen?

arfink · Post by **arfink** » Tue Sep 18, 2007 1:45 pm

aren't those coming OUT of the device you plug into the screen?

Ok, first off, Kyo, no. That is NOT what the -5 volts is. Do not even think about hooking up another devices 5 volt input to that pin. At best it just won't do anything, at worst you'll make your board go up in a flaming pyre. (ok, maybe just a fizzle of smoke, but it sounds cooler to have leaping flames and such!

)

To get a -5 volts input you will need a voltage converter. I believe that an ATX computer power supply will give you a -5 volts just fine, along with your 5 volts, 12 volts, and I think even 1 -12 volts (need to check that)

EDIT: Yup, it has all 4!

Look on Jameco for the converter, they're lots of different kinds that can do this conversion.

One last thing, are you doing a Neo Geo board? If you are, you're in luck, because a Neo Geo doesn't use -5 volts at all, and it only uses the 12 volts for the big audio amp, so if you're portableizing or consolizing, you only need the 5 volts!

Alright, good luck!

Kyo · Post by **Kyo** » Tue Sep 18, 2007 3:20 pm

I know -5 volts doesn't mean that you have to put in 5, I was just saying that you don't have to put anything in becuase those -5 are probably coming from the device, and not the screen.

c_mon · Post by **c_mon** » Thu Sep 20, 2007 5:42 pm

I'm thinking of portablizing a jamma pcb and I think kyo is right that -5 volts coming out, not to be applied. Thanks for your help. Now I need a good game to portablize.