I've found a workable solution for this problem. I did a lot of research on this, so I figured I share the results, though it seems like common sense in hindsight. If you need a NES 72 pin connector for a project you can
- Desolder the connector off a toploader or a famiclone. Depending on what kind of famiclone you may get a surface mount connection instead of through holes. I want through holes for my project, plus I don't want to desolder if I don't have to.
- Desolder the connector off a game genie. This is a pretty good option, but the GG connector must be mounted on the edge of your PCB, which is really hard for prototyping. If you're building your own board, maybe this is ok.
- The 60 pin Famicom adapters are a standard pitch, so you can buy them from Digikey or some place. You can then use a 60 to 72 pin converter. This gives the advantage of being able to accept both Famicom and NES carts, which is nice. However, the pins you are missing include most of the Expansion pins, which I probably want as extra i/o lines for any custom RAM/Flash/EEPROM carts I want to reprogram.
- The 72 pin "replacement" parts are really easy to find, but they are meant to go in a front loader, and have the whole spring mechanism attached. If you haven't seen one, it's basically a "U" shaped adapter with two 72-pin connectors on it. One of them slides over the edge of the main board inside the NES, and the other accepts the NES cartridge. Turns out, both these connectors use the crazy 2.50mm pitch. The connector that the cart normally goes into is mechanically not suitable because of the spring loading mechanism, and it's tilted up at a strange angle. However, the board connector is a perfectly normal card edge. Using a dremel and some wire cutters you can cut the adapter in half, and throw away the oddly shaped connector. Now you have a right angle NES cart connector, with plastic mounting bracket and everything. Of course the 72 pins that go into your PCB are not a normal diameter or spacing, but I don't think that's as big an issue. This is what I'm going to try to use on CopyCart.
Anyway, hope this is useful for someone, or at the very least entertaining