I have vivid memories of this happening a few times, usually during an intense gaming session: the screen would become all garbled and the game would no longer react to input. I’d power down, then power back up again, expecting to get the BASIC prompt, and instead get the garbled image back there on the screen! And yet the C64 didn’t have the type of nonvolatile memory that surviving a powerdown in such a way would imply. The computer would eventually, after a long-enough powerdown, come back to its senses.

As a kid I just attributed this to some advanced sorcery. As an adult the best I’ve been able to theorize is that the crash wasn’t caused by software failure but by the circuitry going awry due to overheating. This misfunctional state would persist even power-off, until the circuitry was again cool enough to function properly. Is this how it happened, or did the C64 actually have hidden nonvolatile memory capabilities far beyond its time?