Typewriters are wonderful. When I was in High School, was into buying any typewriter that an antique shop owner would say was 'completely broken and worthless' and getting it back to a functional state. A typewriter is both a very complex and simple system. The complexity really comes from the weird ways you have to contort the components to get them in and out of the frame. Since the older models were all built by hand, there's always a way to get access to something for repairs. The 'fun' part, however, is always determining the way that that part can be removed. There's always a way, but often there's only one.
Ended up with a completely anachronistic skill, but there's so much that you can get out of doing this kind of apparently pointless repair work.
When I worked at IBM, we hardware engineers were organised into 3 groups. We mainframe engineers went on the cool overseas courses, spent our days in chilled computer rooms and looked after the really important machines. The mid range guys slummed it with AS400s, System 38s and the like typically kept in someone's back office, and went on local training courses only. But the guys that fixed the Selectric typewriters - they were the ones with the real skills IMO. Those things are complex.
[Related Trivia] Selectrics were much more like manual typewriters than people might imagine:
“As with other electric typewriters and electric adding machines of the era, Selectrics are electromechanical, not electronic, devices: the only electrical components are the cord, an on-off switch, and the motor. The keys are not electrical pushbuttons such as those found on a computer keyboard. Pressing a key does not produce an electrical signal as output, but rather engages a series of clutches which couple the motor power to the mechanism to turn and tilt the element. A Selectric would work equally well if hand-cranked (or foot-powered, like treadle powered sewing machines) at sufficient speed.”
Ended up with a completely anachronistic skill, but there's so much that you can get out of doing this kind of apparently pointless repair work.