Norbert Landsteiner does a deep dive into the font of the “Dead Test” diagnostic cartridge of the C64, including an Easter egg, a look into the implementation, and, finally, some Commodore 8-bit character ROMs for download.

The C64 “Dead Test” diagnostic cartridge Rev. 718220 (Commodore part № 314139-03) famously comes with a special font, embedded in its ROM, thus not using the built-in Character ROM of the C64, in fact requiring none of the built-in ROMs to be working (hence the name), as it comes all in stand-alone package.

Its display font is somewhat special and is, to my knowledge, not used anywhere else and, maybe for this very fact, instantly recognizable to anyone who has ever seen it.

Check it out in the post here.