Converting jamma to MVS w/ stereo

cack01

Twinkle Star Sprite
I have the pinouts and I'm pretty much done, but I am confused on what to do with the "speaker pos R" and "speaker pos L" pins. Where do I connect them on the jamma side. My Jamma cab has two speakers, and I am wondering if I just need to rewire the speakers when they connect to the jamma adapter. Or do I just hook both pins upto the "speaker pos" on the Jamma side. Also there is no "speaker negative" on the MVS side, so do I just forget about that pin all together.

thanks for any help.

Also there is a select up and a select down pin. I am guessing I only need to do the select up pin since I have never seen a cab with two game select buttons.
 
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Neorichieb1971

B. Jenet's Firstmate
On Jamma you have L+10 pins which basically hook up to two terminals on a speaker.

Since the L+10 pins become L + R on MVS, you need seperate grounds for the 2nd terminal on the speaker/s.

A simple SPDT switch is what you need to make a cross compatible harness between MVS and Jamma. When switched left, it becomes Jamma mono, when switched to the right pin 10 turns into the 2nd channel of sound.

Obviously this requires some basic knowledge of wiring. You would have L+10 joining the input of the switch, when switch is in position 1 it outputs live and ground to speaker 1 (and or 2 if you have 2 speakers). When the switch is in position 2 (For MVS) pin 10 is re-routed only to speaker 2, with both speakers seperately grounded.


As for select button. If you have a 2 slot, one button is sufficient, since your only toggling between one game and another. For 4 and 6 slot systems, 1 select button is sufficient, but you will have to just toggle more times to get to the game you want. Its no big deal.... Personally, I would keep it simple and use only one button.
 

cack01

Twinkle Star Sprite
Thanks for the reply. Thats pretty much what I thought. I have a 6 slot which I plan to have in this cab for many many years, so I am going to hold off on the switch untill I actually have time to take my time. I guess all I need to do is get in the back of the cab and make sure the speakers are wired up right and make a new ground.

thanks.
 

Neorichieb1971

B. Jenet's Firstmate
If you want everything dedicated for MVS, you would just make sure the left speaker gets pin L (With seperate ground) and pin 10 gets right speaker (with seperate ground).

Then your rocking.
 

ttooddddyy

PNG FTW,
Like this

mvssound.bmp
 

cack01

Twinkle Star Sprite
Thanks ttooddddyy

Now its next to impossible for me to screw up.

Also on something kinda unrelated. Is there any thing I could use as a dust cover for my 6 slot. I'm thinking about cutting a cardboard box apart, cutting 6 slots in it, and then placing it over the PCB. Do people do this, or is there a better way?
 
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