Just picked up one of these babies:
This is an MGCD Dreamcast Jamma adapter. It was only ever sold to arcade distributors in japan, and only by mail. The idea was that it was a cheap alternative to buying a Naomi arcade cabinet. Where a Naomi might cost thousands of dollars excluding the cabinet itself, a dreamcast in those days could be bought for like $100. And since many Naomi titles came to the dreamcast as essentially perfect ports (since Naomi 1 was basically a dreamcast with just more ram), these kits could get you something that feels like a real deal Jamma cabinet at a fraction of the cost.
Inside you see it's actually a stock Japanese Dreamcast secured by a harness that feeds into a small conversion board. That conversion board takes the signal from the dreamcast and converts it into RGB appropriate for JAMMA. The board also provides power through the jamma harness, and feeds the DC buttons into the jamma harness.
There is, in fact, a bug with the harness, though. I suspect these might have, at one point, been supplied with their own cabinets because the harness isn't actually JAMMA compatible. They cut some voltage lines running to the harness to wire up extra buttons, it seems.
My cabinet is actually JAMMA compatible, but has extra kickharness slots for extra buttons (i.e. I don't rock the so-called JAMMA+ "standard" or the NeoGeo JAMMA standard). So, in order to get all this fully working, I'll need to chop up a JAMMA harness and built a custom kickharness. Both of which should be extremely simple (I have spare JAMMA fingerboards laying around anyways).
The front of the converter has a row of dipswitches. These are to change which game it's compatible with. In all, it's compatible with about 75-100 games, mostly ones that appeared on the Naomi or similar arcade games. The machine has hardware that monitor's the dreamcast's video signal, and thus can detect specific screens in games. The way it all works is that the system is basically a gen lock that provides an overlay onto your TV screen to display coin count. If the coin count is 0, then it'll lock the controls so you can't start the game. If the machine detects a game over screen, it'll reduce the coin count -- it's programmed to identify specific game over screens according to the dip switches.
If you play a game that it doesn't recognize, there is a general setting that will instead operate on a timer, where each quarter will grant an amount of time to play, up to 256 minutes per quarter. A timer will display on screen.
In all, pretty swank. I have a JAMMA cabinet all ready to go, I just need to make the appropriate mods on the hardware to get it wired up, then I can enjoy some Marvel vs Capcom 2 and 18 Wheeler American Trucker on my actual arcade cabinet.
These things are super uncommon and documentation on them is really sparse. Really glad to have one.
Here's a screenshot of it running from some dude on youtube:
His screen is oriented vertically for TATE games so it looks wonky as he's trying Virtua Tennis. You can see the gen lock on screen reporting "04" which means 4 credits have been inserted.
Even better is that I have the sega saturn equivalent coming in the mail, too...
This is an MGCD Dreamcast Jamma adapter. It was only ever sold to arcade distributors in japan, and only by mail. The idea was that it was a cheap alternative to buying a Naomi arcade cabinet. Where a Naomi might cost thousands of dollars excluding the cabinet itself, a dreamcast in those days could be bought for like $100. And since many Naomi titles came to the dreamcast as essentially perfect ports (since Naomi 1 was basically a dreamcast with just more ram), these kits could get you something that feels like a real deal Jamma cabinet at a fraction of the cost.
Inside you see it's actually a stock Japanese Dreamcast secured by a harness that feeds into a small conversion board. That conversion board takes the signal from the dreamcast and converts it into RGB appropriate for JAMMA. The board also provides power through the jamma harness, and feeds the DC buttons into the jamma harness.
There is, in fact, a bug with the harness, though. I suspect these might have, at one point, been supplied with their own cabinets because the harness isn't actually JAMMA compatible. They cut some voltage lines running to the harness to wire up extra buttons, it seems.
My cabinet is actually JAMMA compatible, but has extra kickharness slots for extra buttons (i.e. I don't rock the so-called JAMMA+ "standard" or the NeoGeo JAMMA standard). So, in order to get all this fully working, I'll need to chop up a JAMMA harness and built a custom kickharness. Both of which should be extremely simple (I have spare JAMMA fingerboards laying around anyways).
The front of the converter has a row of dipswitches. These are to change which game it's compatible with. In all, it's compatible with about 75-100 games, mostly ones that appeared on the Naomi or similar arcade games. The machine has hardware that monitor's the dreamcast's video signal, and thus can detect specific screens in games. The way it all works is that the system is basically a gen lock that provides an overlay onto your TV screen to display coin count. If the coin count is 0, then it'll lock the controls so you can't start the game. If the machine detects a game over screen, it'll reduce the coin count -- it's programmed to identify specific game over screens according to the dip switches.
If you play a game that it doesn't recognize, there is a general setting that will instead operate on a timer, where each quarter will grant an amount of time to play, up to 256 minutes per quarter. A timer will display on screen.
In all, pretty swank. I have a JAMMA cabinet all ready to go, I just need to make the appropriate mods on the hardware to get it wired up, then I can enjoy some Marvel vs Capcom 2 and 18 Wheeler American Trucker on my actual arcade cabinet.
These things are super uncommon and documentation on them is really sparse. Really glad to have one.
Here's a screenshot of it running from some dude on youtube:
His screen is oriented vertically for TATE games so it looks wonky as he's trying Virtua Tennis. You can see the gen lock on screen reporting "04" which means 4 credits have been inserted.
Even better is that I have the sega saturn equivalent coming in the mail, too...
