What is it?

The Sonic 3 cartridge for the Sega Genesis/Mega Drive contains an FM1208S FeRAM chip for storing its saves. These chips are usually quite reliable, but occasionally they fail. They are no longer produced, but a similar, higher-capacity chip, the FM16W08, is. By pulling the extra address lines to constant levels, we can pretend the new chip is only 512 B like the original. Since the new chip is a small(-ish) SMD, the old one was a huge 600 mil 24-pin DIP, and their pinouts are similar, making an adapter board was simple. This board lets you install a new chip in place of the old one, breathing new life into Sonic 3 cartridges that stopped saving.

This listing is only for the bare PCB, and does not include the FM16W08 memory chip. You'll have to buy that from one of the usual electronics wholesalers and assemble the board yourself.

Why did you make it?

I was one of the unlucky few people to have the original FeRAM chip in a Sonic 3 cartridge fail. Rather than throw the malfunctioning cartridge away, I decided to give it a new memory chip so it can still be used properly. Since I had to order three of the circuit boards from OSH Park, I figured I'd offer the two boards I didn't need for sale here. I'm really just trying to remove clutter by selling these, so I'm selling them at cost.