HackerTube / Video
IBM Selectric Typewriter & its digital to analogue converter
engineerguy
Bill Hammack of engineerguy uses slow motion video to show how the IBM Selectric typewriter works. He focuses on its fully mechanical digital-to-analog converter, which turns key presses into rotation of the type ball.
HN commenters recommend it whenever the Selectric comes up, as a short, excellent explanation of its internals.
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