-5 Volts Question

What the heck is the -5 volts for..?

I've been racking my brains trying to figure out what it does..
Why is it required on jamma boards or harnesses..What does it do..?

I buy MVS manuals,every different one I can find..I like to read them for my own knowledge..
The one manual I have for making a neo geo conversion cab does show the -5 volt on a jamma harness and what other wires are required to make it work for MVS..
But the don't say to remove that -5 volt wire..at least I don't see that..
So what happens if you leave this -5 wire hooked up on a MVS harness going to an MVS board...?

When I look at my power supply like the one in the link below..
It has -5v ..and looks like it's going up to the harness..through the plug..
I have to trace it to the harness..and look again tomorrow.

But If I do find out it's hooked up to the harness should I remove it..?
My Red Cabs working great,but if this -5 wire is not supposed to be used and can cause a problem then I'd like remove it if that's the case..

+5v 15A, +12v 5.5A, -5v 1A
UL recognized, CSA
Over voltage protection on +5v, a Happ exclusive
Designed specifically for the coin-op industry
Smoother start-up
Better heat dissipation: three separate heat sinks
Dual AC input 115vac/230vac, selectable by switch
Low ripple and noise, EMI filter
Complete overload and short circuit protection
Built in DC fan and power switch
Metal case - XT size
Requires minimum 1.5 amp load on +5 for proper operation
Supplied with 6' long SJT power cord


http://www.happcontrols.com/powersupplies/80001500.htm
or
http://www.happcontrols.com/powersupplies/80007200.htm
....................................
If I'm talking crazy then tell me I'm talking crazy..
Sometimes I think to damn much about this stuff....

-5V is used in some older jamma games but it's not in use on MVS boards, there's not even traces from the pins on the board. You can verry well leave the -5v if you do have it as it des no harm, your just taking the pinout further from the plain jamma standard.

-5 volts are seldom used in games and not used in Neo's wiring scheme. Last time I seen the -5 used in a game were mostly pre 1990 cabinets. The JAMMA supports it in the event you decide to convert a non-JAMMA board to it and have the need for -5.

All of the 90's Midway games using the DCS sound system(and maybe the earlier ones) require the -5V for the sound to work. I think it was for the audio opamps. Not sure about others.

Reznor007 said:

All of the 90's Midway games using the DCS sound system(and maybe the earlier ones) require the -5V for the sound to work. I think it was for the audio opamps. Not sure about others.

Click to expand...

Oops! Forgot about those. Thanks for the reminder

Did I read somewhere that the Neogeo hyper 64 (earlier version boardset) uses -5 for the audio op-amps. Im sure I have a schem somewhere ? searching.

ttooddddyy said:

Did I read somewhere that the Neogeo hyper 64 (earlier version boardset) uses -5 for the audio op-amps. Im sure I have a schem somewhere ? searching.

Click to expand...

Yes it did. That is why I wired a -5 in my candy, only to receive a ver. 2 board that didn't require it

« PESTILENT » said:

Yes it did. That is why I wired a -5 in my candy, only to receive a ver. 2 board that didn't require it

Click to expand...

Oh well it may come in use for some other boards