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I've been mulling this project over after seeing the detailed surgery required to turn an old TI game cartridge board into a fully-functional Supercart. The current method leaves a lot to be desired--and a lot of room for error. Springing off from that point this weekend, I've done a layout specifically designed to be used as a 32K Supercart (it gives the user 4 banks of 8K each, switch controlled). Both chips can be socketed, as can the coin cell battery to back up the RAM contents. If there is enough interest in them, I may do a small run of the boards for the community, otherwise, I'll just get a couple of them made for my own uses.
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Exactly, Steve. The board had enough space to put both chips (32Kx8 and E/A GROM) in positions that didn't interfere with the case or the battery holder. I'm still trying to figure out if there is enough real estate available in the right area to switch out the resistor/diode matrix for the battery with an 8-pin DIP that does an even better job at switchovers, but it may be a bridge too far on this one due to space limitations. The battery holder and the 32K chip each chew up a lot of space in that part of the cartridge case. I could probably do it by not socketing the 8-pin chip (a DS1210), but I am a bit loathe to go that route.
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It is a nice thought, but the space below the board is only a shade more than 3/16 of an inch--about 1/16 too little for our purposes. I still have to do some tinkering to see what I can fit into the board--and I have to be careful not to break compatibility with the boards that preceded it. I may just do a small run of 10 or 20 of these to verify that all of my original assumptions are correct and then proceed to do a modified board that adds the additional functionality we want, assuming I can make everything fit. . .and I can do that, if I abandon the goal of putting the chips in sockets. That gives me a lot more usable real estate. . .
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I'll have to look at that one. . .
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I finally did some tests with the updated 32K Supercart boards. The layout works well and everything fits perfectly into a cartridge case if you put the correctly-sized switches into the case, oriented sideways. I made more of them than I need, so the bare boards will probably show up sometime soon on the Arcadeshopper webstore.
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I had 40 of them made, Steve. I doubt I'll ever sell more than 20 of them, but the difference in price for the additional 20 boards was low enough that it made sense--as then I would never need to do another run of them again, even if demand was higher than I expected it to be. Even the additional overhead for the slightly larger run leaves the boards highly affordable (I plan to put them up on the Arcadeshopper site for $10 each as a bare board--pretty much a standard price for a bare cartridge-sized board). I built four of them as my test objects (and I haven't taken any pix yet, but I'll put some up once I do), but I only have one loose E/A GROM right now, so only one was put into a cartridge case after I completed testing on them. One of the other three test boards was sold before I finished the assembly. . .to someone who already had an E/A chip for it.
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Hi, Guest
