• Commodore’s RAM Expansion Units (REU) were bulky cartridges that required a heavy duty power supply when used with the Commodore 64. With 512K installed, the 1750 was the largest capacity REU that was offered. Some users upgraded the 1750 up to 2MB by adding additional RAM chips and a small hardware mod.

    The CMD 1750XL is a clone of the Commodore 1750 REU that includes a full 2MB RAM pre-installed. A small number of software programs, notably GEOS, could take advantage of the entire 2MB RAM as a large RAM disk.

    The 1750XL used the same REU controller chip as the Commodore REUs for full compatibility. By using more modern RAM chips, the 1750XL is housed in a much more compact cartridge that can be used with the standard Commodore 64 power supply.

    The four ZIP packages are Toshiba TC514400AZ-80 chips (1MBx4 DRAM) for a total of 2MB. The chip labelled “REU-3900A” is a GAL20V8A-15LNC.


    Toshiba TC514400AZ Datasheet