Mortal Kombat Y Unit

[xrodney]

Does the mortal kombat y unit board need -5v???  i have a couple of boards, and when i connect the sound board, it automatically restarts and either there is no sound or scrambled.  this is the first time i am connecting an mk1 y-unit.  i have a 2 in 1 jamma switcher and it does not have -5v.  should i try and connect it to my mk2 cabinet?  according to the manual, it needs -5v at 1A, but some say that -5v will burn a y-unit mk1

feedback is appreciated

Rodney

[mvsfan]

well, According to Mikesarcade.com, Theirs only 1 mortal kombat jamma pinout for their lack of including an alternate one.

Ive used this site for a long time in building adapters for non jamma games and in every case ive had no matter the game, they are spot on.

so what i get is that your MK needs -5v to function.

I dont know for sure cause ive never looked into multi adapters

but my guess is that if you only have -5v on all the time, the board could not function and your board in the multi adapter that has all signals on would be dominant.

other thing is this.

many multi jamma boards ive read about supply power to both pcbs all of the time, and only switch video, sound, and controls.

in that case you should be ok to hook up a -5v wire from the PS to the MK Board without a problem, and it should light up.

Id like for anyone who actually know though to contribute before you try it.

[mvsfan]

also, Look on the board itself and see if traces lead from the -5v on the card edge to somewhere else on the pcb. IF they dead end at the card edge, the board doesnt use it and same goes for other pins too.

[MonMotha]

Most Midway stuff uses -5V for the small signal audio processing.  I do believe that the sound stuff used by original MK is amongst them.  I know the DCS board used by MK2 is, and I know the NBA Jam board also uses it, and I think it was the same board as used by MK for sound.

The game will run without -5V, but you won't get any audio.

No JAMMA game should be damaged by properly wired -5V.  It's part of the "standard" that it be present, but some boards don't use it.  Things that aren't actually JAMMA compatible may re-purpose those pins, but I don't know of any examples off the top of my head that are keyed like JAMMA that actually do something that silly.

[Kevin Mullins]

Yes, as mentioned.... it requires the -5v.
For whatever reason all the multi pcb "switchers" I have seen leave the -5v dead ended, You will have to modify your switcher and run the -5v appropriately.

There have been several people on this forum that have done it, it's not that difficult.
(just annoying to have to do it at all)

http://forum.arcadecontrols.com/index.php?topic=90288.0