The Commodore 64 was the computer of the 8-bit era, and remains the highest selling computer of all time. In addition to disk and tape drives, it also had a cartridge interface. A popular extension cartridge was the final Cartridge III, which used a variety of disk utilities and a GUI. [Greisi] was in possession of a no longer functional cartridge, and made a decision to reverse engineer the device.

[Greisi] started by desoldering all the ICs and mapping out a schematic for the board. The design centers around common parts for the era, such as a UV-erasable EPROM and some 74-series logic. [Greisi] made a decision to then modernise the design and make some improvements. adding a fuse must avoid the cartridge catching on fire, and a bunch of decoupling capacitors on all the ICs must minimize noise. A FLASH chip is used instead of the old school UV-erasable part, which makes writing to the device much easier.

It’s a terrific build done in a stunningly tidy workshop, and [Greisi] has supplied the schematics and PCB designs to the public here. That means that lots of a lot more users can build their own final Cartridge III without having to hunt for original hardware which is growing scarcer. You can learn a lot more about the final Cartridge III on Wikipedia.

We’ve actually seen the final Cartridge III before – used in this blinkenwall installation. Video below the break.

[Thanks Adrian!]