Thomas Christoph recently shared an update on the progress of his work on the CMD 1750XL project. Earlier, he demonstrated the feasibility of replacing the 64-pin DIP REC chip used in the original CMD 1750XL with the 68-pin PLCC REC chip found in Commodore’s 1764 and 1750 REUs. After successfully reverse-engineering both the GAL and PCB of the original CMD 1750XL, Christoph moved on to translating the design into a schematic and creating a new cartridge board utilizing the PLCC REC chip.
His efforts have yielded a fully functional CMD 1750XL PLCC edition cartridge. This updated version operates identically to the original but features the square 68-pin REC chip. While the PCB dimensions are nearly perfect, they require slight adjustments before finalization.
The goal of the project is to allow users to repurpose the REC chip from their existing Commodore REUs, install it onto this new board, and transform it into a 2MB CMD 1750XL REU. Christoph also revealed prototype photos of the PLCC edition board, noting that the final version will feature ENIG (gold-plated) finishing. A side-by-side comparison of the reverse-engineered original and the PLCC edition recreation.
