How to build a multi jamma?

[littlecharlie]

HI, does someone know how to build a double jamma, to switch between 2 jamma pcbs?
I know there are some commercial multi jammas, but i'd like to build my own.

Thanks

[CheffoJeffo]

The answer to your question is "Yes", but can you be more specific as to what you are looking for ?

Do you want to build your own JAMMA switch ?

Mechanical vs. Electronic switching ?

Do you want the boards to be powered the entire time ?

Controls connected to both games and just audio/video switching ?

[littlecharlie]

Hi CheffoJeffo

The answer to your question is "Yes", but can you be more specific as to what you are looking for ?

Do you want to build your own JAMMA switch ?
Yes

Mechanical vs. Electronic switching ?

It would be great if i could do it by electronic means, eg, using a button to switch between pcbs

Do you want the boards to be powered the entire time ?

I don't really mind, just the easiest way. But if I had to choose, I'd choose that the boards only were powered when they are selected

Controls connected to both games and just audio/video switching ?

That's it!

Thanks!!!

[littlecharlie]

Hi!

Anything new?

CheffoJeffo?

[CheffoJeffo]

Patience paduan -- what has it been, 16 hours since I asked clarifying questions ?

It's not like I am going to design the circuitry for you -- *I* buy my JAMMA switches because it isn't worth the time to make them for *myself*, let alone design them for someone else.

[jimkirk]

 *I* buy my JAMMA switches because it isn't worth the time to make them for *myself*, let alone design them for someone else.

I agree,by the time you buy materials and spend hours designing and building the switcher,it would be cheaper and way easier to just buy the damn thing and go on to other projects.
I would just buy the 6 in 1 so you have the option to put other boards in later if you want.
I have 6 boards in my cab.

Edit: I found this on ebay,pretty good deal.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=310118028006&category=13718&_trksid=p3907.m263&_trkparms=algo%3DSI%26its%3DI%26itu%3DUCI%26otn%3D15%26po%3DLVI%26ps%3D54

[littlecharlie]

It's not only a matter of money (even if the shipping costs to Spain make the item less interesting), it's a hobby.
I'd like to spend some of my free time making this multiple jamma by my own.
I've made an arcade control, a supergun, and my next target is a double jamma.
All I'm asking here is if someone can help me out ...
Any schemes? any advise? the theory of what should I do?

pd: it's not always easy to understand what you mean for a non enslish-speaking person

[polaris]

It's not only a matter of money (even if the shipping costs to Spain make the item less interesting), it's a hobby.
I'd like to spend some of my free time making this multiple jamma by my own.
I've made an arcade control, a supergun, and my next target is a double jamma.
All I'm asking here is if someone can help me out ...
Any schemes? any advise? the theory of what should I do?

pd: it's not always easy to understand what you mean for a non enslish-speaking person

if making a jamma switch proves to be difficult, maybe Grantspain who posts here could help you find a supplier in europe.

[littlecharlie]

Ok, but my priority is to try to build one.

I will appreciate any help on how to do it.

[venkman]

i have a machine that has two games.

it has one pcb that seems to simply route the signal from the other two. both stay powered all the time - so when i press the button on the front it just switches the signal from one to the other.

here's a picture:




i didn't build it tho' ..  i bought it like that.

[littlecharlie]

I guess nobody in this forum has ever built a double jamma.
Although I though maybe somebody knew the theory or the steps to build one.

[CheffoJeffo]

There have been a number of folks who have built game switchers, but pretty much nobody builds them for JAMMA because there are a number available for relatively good prices.

The questions that I asked in my first response are important and completely determine the way to go.

For example, if you want to build a mechanical switch -- just hack a mechanical switch like a parallel port switch (you may have to do something different for power, depending on the underlying switch).

If you want to build an electronic switch, then you might start looking into relays and switching circuits (and may then see what I mean about using the existing alternatives).

And knowing how does not always equal "willing/able to spend the time designing stuff from scratch for no money for somebody else".

[littlecharlie]

There have been a number of folks who have built game switchers, but pretty much nobody builds them for JAMMA because there are a number available for relatively good prices.

The questions that I asked in my first response are important and completely determine the way to go.

For example, if you want to build a mechanical switch -- just hack a mechanical switch like a parallel port switch (you may have to do something different for power, depending on the underlying switch).

If you want to build an electronic switch, then you might start looking into relays and switching circuits (and may then see what I mean about using the existing alternatives).

And knowing how does not always equal "willing/able to spend the time designing stuff from scratch for no money for somebody else".

yeah, I once though about the option of using a parallel port switch (for printers)

but it was quite large and would rather have an electronic switch.

The theory, for e-switch, seems quite easy. Just switch the control pinouts from the jamma to either one pcb board or another (pins from J to c).

But all the multiple jamma that I have seen, have lots of stuff (switches and lots of other components). And that makes me suspicious that it is not so easy.

Finally, I recognize this might be "losing time", and spending the money in one commercial and easy to find multiple jamma is the smartest option. But it's just my decision of trying it, and maybe, who knows, eventually, i'll give up.

[BobA]

J to c only covers one side of the PCB connector 10 to 25 are on the other side.   Based on keeping power on both boards you would not need isolation of the circuits if you switched mechanically if you electronically switch and leave power on both boards then some diode isolation will probably be required.  Take a look at some of the 2 board electronically switched units and you can probably guess which ICs they are using and whether or not they put in isolation.