When I got the keyboard the exterior was in pretty rough shape after decades of storage.

While the keyboard was disassembled for cleaning, I took some photos of the interior. Happily, none of the keyswitches was the slightest bit damaged.

The keyboard runs off an 8048 microcontroller with built in storage, probably "mask programmed" at the factory with the final code.

With just soap and water on the plastic case & keyswitches, it cleaned up beautifully!