My Neo Geo Cab - A little help?

[Vicked]

Hi All

I recently purchased a 2 slot Neo Geo cabinet. The screen is working but the motherboard isn't, when I turn it on some Japanese text appears.

Regardless, I want to pull out the motherboard and put a MAME computer in anyway.

I've done alot of reading and I have a couple of questions:

1. I couldn't find any other projects converting this rather standard looking Neo Geo cabinet, could someone point me in the right direction? I'd like to have a look and see how others have done it.

2. In the picture of the insides, am I right in saying the JAMMA connector is the connector connected to the side of the motherboard? (MB on the left under corroded metal shield)

3. I have read about the J-Pac and the ArcadeVGA devices. Will the J-Pac take the VGA output from my Radeon 9550 and send it straight to the Monitor, or do I need to get an ArcadeVGA and connect it to the J-Pac? Will using the original monitor stop me playing other emulated systems such as Nintendo, SNES, Sega Genesis, Amiga etc?

Thanks in advance for taking the time to answer my queries, I have tried to locate the answers myself and I'm pretty sure I know the answers, but just want to double check.

[Witchboard]

Could you get a picture of the Japanese text?  According to HardMVS it's a Pacific region cabinet.  Pretty cool looking.  You can get more info here.  The multi-slot MVS aren't JAMMA so you'll have to do some rewiring.  Should be pretty simple though.

[Thargok]

If it is fixable, fix it.  Sure there are tons of them, and it isn't historic...YET.  For the love of all that is holy see what you can do before you destroy a beautiful piece of art.

[Vicked]

Are you sure it isn't Jamma? I was told it was. Also the guy at the place I bought it plugged in a Street Fighter motherboard which he said was JAMMA and it worked.

When you turn it on there is a high pitched whining noise. Sometimes there is some garbled text showing which on second inspection probably isn't Japanese - its probably just random characters. Most of the time the screen is just white though. Note that I have no cartridge (did try it with a cartridge at the place and it didn't work).

My plan is to remove the Motherboard and put in a computer, I don't intend on harming the exterior or control panel if possible.

[Witchboard]

There are a few minor changes between the MVS and JAMMA wiring harness.  Here's a link explaining the differences.    True the Street Fighter worked, but note street fighter uses 6 buttons, and you lacking the kick harness didn't keep it from working.

The high pitched whinning noise is most likely caused by bad EL pads.  They are what light up the mini-marquees in the header.  This is normal and will stop when you remove the connection from the motherboard.  You should have a cross-hatch sceen if the board is working without a cartridge.  Check and make sure all the dip switches are turned off.

[Vicked]

@Witchboard

Thanks for the info. What exactly is a cross-hatch screen?

So, can I get some feedback on this:

If I follow the instructions here (http://www.hardmvs.com/html/jammaAdapt.htm) and make a JAMMA adapter, I could then use a J-Pac to interface my computer to the Cabinet (controls and video etc)?

Do I need an ArcadeVGA in addition to the J-Pac?

[Jess--]

if you are planning on using a normal PC in place of the neo board I would suggest that you get yourself an arcadevga card from ultimarc, it is by far the simplest way of connecting to a standard arcade monitor.

[Vicked]

@Jess

If I get an ArcadeVGA card, do I also need a J-Pac?

[Witchboard]

@Witchboard

Thanks for the info. What exactly is a cross-hatch screen?

It's a screen that has horizontal and vertical lines so you can adjust your monitors convergence and size.

So, can I get some feedback on this:

If I follow the instructions here (http://www.hardmvs.com/html/jammaAdapt.htm) and make a JAMMA adapter, I could then use a J-Pac to interface my computer to the Cabinet (controls and video etc)

If you plan on removing the Neo-Geo board, I wouldn't bother with an adapter.

[CheffoJeffo]

If I get an ArcadeVGA card, do I also need a J-Pac?

What about video?

The J-PAC routes VGA video from the PC VGA card to the JAMMA connector and therefore to the monitor. But of course it's not that simple! There are configuration issues when using arcade monitors on a PC with a normal VGA card (as opposed to our ArcadeVGA card). The VGA card must be told to output a horizontal sync frequency which is much lower than the VGA standard. The J-PAC amplifies the VGA 1 volt signal level to approx 5 volts peak-peak which is the arcade monitor spec.

What does the J-PAC video circuitry do?

Besides amplifying the video level, the on-board video circuitry also synthesises composite sync from separate H-V sync from the VGA card. The J-PAC has a jumper which is set to the frequency that the monitor is designed for (most commonly 15Khz). 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. IMPORTANT: It is not a scan converter so you will have to configure the VGA card to send the correct sync rate for the monitor OR you can use our ArcadeVGA card which will drive a 15Khz monitor with no special configuration.

How does the J-PAC work with the ArcadeVGA card?

The J-PAC and the ArcadeVGA card (see details under ArcadeVGA heading) make perfect partners and give the easiest possible solution for driving a JAMMA cabinet with a 15Khz monitor. The ArcadeVGA card plugs into the PC and simply plugs into the J-PAC via the VGA cable. Then plug into the cabinet harness and you should get a perfect picture right from boot-up with no worries about configuring the VGA card to send 15Khz.

http://www.ultimarc.com/jpac1.html

In short, yes .. the JPac and ArcadeVGA have very different, although complimentary, purposes.

Cheers

[Vicked]

@CheffoJeffo

Thanks, exactly what I was after.

@Witchboard

If I don't make a JAMMA adapter how do give the inputs to the J-Pac?

What is the simplest way to get the controls and screen to mate with my computer? I'm assuming I could use a keyboard hack and some sort of monitor hack/interface (to connect to the ArcadeVGA).

[Witchboard]

@Witchboard

If I don't make a JAMMA adapter how do give the inputs to the J-Pac?

You can move the pins in the connector, or you can just re-wire the cabinet.  The differences are minimal, but there.  If you plan on putting a MVS board back in there, or fixing the one you have then build an adapter.  Either way if you put the JAMMA and MVS pinouts side by side it should be pretty easy.

[Havok]

If it is fixable, fix it.  Sure there are tons of them, and it isn't historic...YET.  For the love of all that is holy see what you can do before you destroy a beautiful piece of art.

No offense to Vicked, but that cab is not what I would call beautiful. It's a rather boring looking box, with a monitor in it. But it's all about the games, so who cares, right? It's definitely got some potential...

[quadmasta]

did you get rid of the game board yet?

[Vicked]

Hi Quadmasta

I still have the board, I'm trying to fix it at the moment. No luck yet though.