People who follow the PGM Conversion thread may know that I'm working on replacement PCBs for IGS Polygame Master, so people can make cartridge versions of the three CAVE shooters without sacrificing donor carts for the PCBs.
My current version has a few flaws, a major one being that I messed up the address decoder for the sample ROM:
Features:
- 27c322 EPROMS - so no messing around with voltage regulators or running chips out of spec
- should work for all three CAVE titles
- only uses through-hole components
- ENIG gold plating
Problems:
- footprints for capacitors are very narrow (fixed in version 1.1)
- the board fit into the cartridge shell is a bit tight (fixed in version 1.1)
- the logic chips are a bit close to the pcb edge (fixed in version 1.1)
- the two address decoder pins marked above are swapped. So when installing the 74LS139 you'll need to lift pins and connect them to the correct pad with wires... (fixed in version 1.1)
Limitations:
- this is only a replacement for the graphics board so far. For a full conversion we'll need a program board as well, and I need a few of the remaining mysteries solved before I'm comfortable ordering PCBs.
- this is NOT a multi-cart, and my focus are the CAVE games. (Other games may need more ROM space, and a different sample ROM decoding logic.) If you're after a proper multi-ROM it'll be worth waiting for whatever Darksoft will cook up.
- the 27c322 EPROMs are obsolete, so you'll probably have to get recycled ones from eBay.
- I installed the chips into sockets in the image above, but the board will NOT fit into the cartridge this way.
- the board is not really usable for mass production, you'll probably want larger ROMs which are only available as SMD components. And installing recycled EPROMS with crooked legs is very fiddly.
I'll get new boards made when I finish the program board, so I want to use this chance to get some feedback. I'm willing to send a few of the board away for people to test, providing:
- they pay for postage
- they make a small donation to charity
- they should already have a CAVE conversion to compare against, or be prepared to convert a program board (Any PGM Conversion info out there? for compatible program boards.) It should be enough to swap the EPROM with the program, then you'll just have to play with corrupted background graphics...
- they are able to do the soldering and EPROM programming (and possible debugging) themselves. I can't do support, as I hardly know what I'm doing myself...
My current version has a few flaws, a major one being that I messed up the address decoder for the sample ROM:
Features:
- 27c322 EPROMS - so no messing around with voltage regulators or running chips out of spec
- should work for all three CAVE titles
- only uses through-hole components
- ENIG gold plating
Problems:
- footprints for capacitors are very narrow (fixed in version 1.1)
- the board fit into the cartridge shell is a bit tight (fixed in version 1.1)
- the logic chips are a bit close to the pcb edge (fixed in version 1.1)
- the two address decoder pins marked above are swapped. So when installing the 74LS139 you'll need to lift pins and connect them to the correct pad with wires... (fixed in version 1.1)
Limitations:
- this is only a replacement for the graphics board so far. For a full conversion we'll need a program board as well, and I need a few of the remaining mysteries solved before I'm comfortable ordering PCBs.
- this is NOT a multi-cart, and my focus are the CAVE games. (Other games may need more ROM space, and a different sample ROM decoding logic.) If you're after a proper multi-ROM it'll be worth waiting for whatever Darksoft will cook up.
- the 27c322 EPROMs are obsolete, so you'll probably have to get recycled ones from eBay.
- I installed the chips into sockets in the image above, but the board will NOT fit into the cartridge this way.
- the board is not really usable for mass production, you'll probably want larger ROMs which are only available as SMD components. And installing recycled EPROMS with crooked legs is very fiddly.
I'll get new boards made when I finish the program board, so I want to use this chance to get some feedback. I'm willing to send a few of the board away for people to test, providing:
- they pay for postage
- they make a small donation to charity
- they should already have a CAVE conversion to compare against, or be prepared to convert a program board (Any PGM Conversion info out there? for compatible program boards.) It should be enough to swap the EPROM with the program, then you'll just have to play with corrupted background graphics...
- they are able to do the soldering and EPROM programming (and possible debugging) themselves. I can't do support, as I hardly know what I'm doing myself...
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