For this #wedNESday, I am sharing my black label version of Urban Champion for the Nintendo Entertainment System (NES). The game itself is a fairly basic fighting game. It isn’t particularly deep, but it is also fun for a quick play. It was originally released in Japan in 1984 on the Famicom and eventually made it to North America in 1986 for the NES.
— Nate 🎮 (@RetroGamingDev) June 6, 2018
What is so special about the 5 screws in the cartridge shell? Well, possibly nothing. But, it is also possible that this cartridge contains a Famicom converter.
Back when Nintendo was making it’s first push into NA, they were under heavy deadlines to provide product to their vendors. Instead of shorting them and pushing out shipments, they decided to use some of their existing stock of Famicom game boards. Both consoles used the same architecture and programming, the games worked fine. That is save one issue – the Famicom used a 60 pin connector and the NES used a different 72 pin connector. Nintendo added some additional piracy protection with the 10NES lockout chip which utilized the additional pins. To deal with this, Nintendo added a conversion adapters into these games that were using Famicom boards.
What does this mean for us today? Well, if you have one of these adapters, you can extract it and use it to play imported Famicom games on your NES consoles. These cartridges are also considered to be more rare, so it could also have additional value for collectors. The adapter boards are most typically found in carts with 5 screws. Later in the NES lifespan, cartridges were redesigned to use a 3 screw layout and this was well after Nintendo stopped using the Famicom adapters.
Do you have any 5 screw carts? Have you checked to see if you have a Famicom adapter?
NOTE: All of this information is what I have learned from reading various sources on the internet and input from users on Twitter. It is possible I have incorrect information and I am happy to make updates to my explanation if that is the case.