Micro Switch 63SC31-1 prototype
The photos below are archived from eBay listing 223782018077 “Rare 1970's? Micro Switch Engineering Computer Keyboard Prototype! No Reserve!” from seller dan123.813; the original listing has since been deleted by eBay. It is an engineering prototype of Micro Switch SC Series model 63SC31-1, with serial number B108. The date of production appears to be 1980, based on having ICs from 1979 and 1980. The keycaps appear to all be labelled, possibly over blanks.
