Jamma to MAME help?

[Aceldamor]

I have read a few sites/posts about converting a Jamma box to MAME.


I wanted to tap the pros here though for some potential help.


My buddy is buying a JAMMA showcase cab that was running Tekken 4. He is all about making it a MAME box, and has asked my help in converting it. I don't think he's too big on keeping it JAMMA ready if he doesn't need to, however I was just wondering if there was any way short of hacking a VGA cable, or buying the UV card from Ultimarc?

I'm thinking it would just be easier to hack the VGA cable, and re-wire the controls through a standard GP-Wiz or I-PAC. That way, if he wanted to, we could pull the MAME out of the box, re-use the JAMMA harness and wire the Monitor back if he wanted to sell it some day.

Just wanted to get some input from other folks who might have done this.

Thanks for the input guys,
Ace

[Malenko]

you can hack a VGA cable, run soft 15, and wire controls through an IPAC (or IPAC2)

or

you can get an arcadeVGA card and a JPAC then the jamma buttons will already be wired, you'll just have to wire the extra buttons to the JPAC

[CheffoJeffo]

I'm thinking it would just be easier to hack the VGA cable, and re-wire the controls through a standard GP-Wiz or I-PAC. That way, if he wanted to, we could pull the MAME out of the box, re-use the JAMMA harness and wire the Monitor back if he wanted to sell it some day.

That is exactly the opposite of what I would do to achieve the goal of being able to yank the MAME box and restore to JAMMA.

For the sake of simplicity, there are 3 "things" that can run through the JAMMA harness when you use a JPac -- Controls, Video and Audio.

The only difference (assuming a 2-player CP) between running through a JPac or an IPac is that with a JPac you only need to wire the "extra" buttons, because everything else is already connected via the harness. To use an IPac, you will need to disconnect everything from the harness and then reconnect to the IPac. It's not a big deal, but it is bloody convenient using the JPac.

As far as video goes, regardless of whether you use the JPac or a hacked VGA cable, you still need to get your video card putting out at 15Khz. You can do that using soft15 or using an ArcadeVGA. The JPac is nice because it won't send a bad sync rate.

The J-PAC will not pass the sync signal through unless it detects the signal is at the correct frequency for the monitor. Some older types of 15Khz monitor could be damaged if fed with a high sync rate. The J-PAC prevents this happening. If the sync rate is not in range, the monitor is still powered up and still has video passed to it but no damage can occur as the horizontal frequency cannot be driven too fast without any sync present.

And the JPac is marginally easier to hook up than hacking a VGA cable.

Which brings us to what I consider the only weakness to the JPac -- audio. JAMMA standard is amplified mono. Your PC (typically) puts out unamplified stereo. Andy's advice has been to use amplified speakers instead of the speaker installed in the cab. It's a reasonable thing to do, especially if you want to use the cab as a jukebox. What I do is run the sound card output to an amplifier circuit (something like these), which I power from the +12V from the power supply and then into the speaker inputs on the JPac.

FWIW, I almost always use the JPac as my main interface in MAME projects now. It's quick and allows me to repurpose the cabinet easily should I decide to use it for something else other than MAME.

By way of an example, I had an old MAME rig that I set up a few years ago for a vertical MAME cabinet. I later decided that I wanted to just drop in a 48-in-1 board instead. It took me less than a minute to pull out the old rig, connect the arcade power supply and install the 48-in-1. This past weekend, I ended up putting that same MAME rig into a JAMMA cabinet for a trackball/spinner-based horizontal MAME cab (note: the trackball and spinners don't run through the JPac -- I used it for ease of connectivity). It took me less than 5 minutes to pull out the Golden Tee board and power supply and install the MAME rig, including power and connecting the trackball (I still have to decide on what spinners I want to use).



Going the JPac route works really well for me and gives you the ability to instantly convert back to JAMMA.

[Aceldamor]

Thanks for the replies so far guys, really helps me along

I have some new information.  He currently has a 2p 4 button layout that he wants to convert to 4P with players 1 and 2 with the 6 button layout, and 3 and 4 with 4 button.

I know Jamma lets you do that, however I'm not to Jamma savy, so I wasn't sure how tough it would be to do. I really appreciate the help guys!

Thanks,
Ace

[CheffoJeffo]

That revelation changes things a bit.

JAMMA supports 2 players each with a joystick and 3 buttons (some games support a fourth button on the JAMMA harness at pins c and 25).



The JPac supports buttons 4 through 8 via screw terminals.

If you want to go 4 players, then you can (and I would) use a JPac and an IPac2 with P1, P2 going through the JPac and P3, P4 going through the IPac.

At this point, however, there will be folks who would tell you just to use an IPac4 and rewire the whole thing from scratch. And it wouldn't be bad advice, even though I would probably still use the JPac and an IPac2.

[Man_Utd]

What about five joysticks?  The fifth being a 4 way.  Would you use a IPAC4 instead of an IPAC2?

Also, if you were to use an IPAC4 instead of the combination of JPAC and IPAC2, would you have an issue with supporting an arcade monitor (15kHz)?

[CheffoJeffo]

What about five joysticks?  The fifth being a 4 way.  Would you use a IPAC4 instead of an IPAC2?

No -- I would wire the 4-way up to one of the other joystick controls.

Also, if you were to use an IPAC4 instead of the combination of JPAC and IPAC2, would you have an issue with supporting an arcade monitor (15kHz)?

Doesn't matter which you choose -- you are always going to have some issue with supporting the arcade monitor. The biggest issue is getting your video card to drive at 15kHz. The JPac just makes the connection easy (plugging in a VGA cable) and will block a bad signal, preventing possible damage to your monitor (which you will have to do manually otherwise).

[ZEN]

Gentleman,  question on your posts above.  I too have a 4 player Jamma Cab/new project that I am starting to Mame, but would not mind keeping open to refurbish back to pcb/jamma at some point.  If I am understanding you correctly, I can use my Jpac and IPac2, still utilize a 5th controller (4-way), by running this controller parallel/simultaneously with player 1 controls?

Can I still run an optipac with this setup?
 would I still need the power supply?  I would keep the monitor and run off the Iso transformer, but I guess I would disconnect the supply to Jamma I would assume?  Sorry, still grasping the 110v concepts ......

With the JPAC, it sounds like I do not need the video amp for the monitor, do I understand this properly?

Thanks guys, sorry if the answers to my questions are already in this post......

[Turnarcades]

The safest way is to get an arcadeVGA to get that signal at 15khz, then use at least a j-pac. If future expansion is required you can add any combination of other '-pac' family interfaces, as long as they are programmed whilst plugged in individually.

If you intend to use seperate buttons/joysticks for dedicated games then the best way to go is to wire them to the same inputs as player 1's regular controls. As you will not be using the regular controls, the dedicated sticks/buttons will just activate the same key presses as the regular controls do, ridding you of the need to have extra inputs/interfaces or reconfiguring control layouts specifically for the dedicated stick/button inputs.