When IBM released its729 Magnetic Tape Unit in 1959, Eisenhower was the sitting president. Alaska and Hawaii had just been admitted to the union as full-fledge states. No human had yet been in space. And debugging computers was very, very different than it is today.
IBM's 729 storage device kept its data on half-inch-wide strips of tape that could be nearly half a mile long, queued up for read-write access by no less than eight internal motors and the help of a few vacuum tubes to cushion rapid jolts that would threaten to snap the ribbons in half. With a cruising speed of 75-inches per second (a little over four miles per hour), machine's reels of tape were cable of a respectable 120 kbit/s data transfer speed, or ten times slower than even a sluggish 3G cellphone connection.
So when the IBM 729 that lives at the the Computer History Museum began having some read-write errors last April, there were any number of things that could be going wrong. Ultimately, the issue came down to a failing "brush block," a small plastic box with metallic brushes designed to make constant contact with a metal disk and conduct electricity to it. Identifying it was one thing. Fixing it was a whole other journey, as documented by CuriousMarc, YouTuber and Astromech engineer:
The construction and replacement of these brushes was surely difficult even back in 1959, but here in 2016 it comes with some new tangles. Coming up with replacement parts required a whole team of enthusiasts to make and spool the appropriate wire from scratch. It was only after that, as CuriousMarc notes in the video's description, that the team could spend some three hours attempting to install them before ultimately coming away successful.
Read more here: www.popularmechanics.com/technology/a21586/debugging-1959-vacuum-tape-drive/