Fixed: Philips PM 3234 analog storage oscilloscope. There was the occasional jitter on the trace in the time axis, as if the trigger circuit was acting up. And sure enough, after reading the trigger section of the service manual and tweaking the right potentiometers, it works fine again. What a beauty this is. I gave it to a friend in exchange for something else that's pretty damn cool. More on that later.

Got: books!

Got them from a retired physicist who ran his own software company from the mainframe era of the 70s up until the early 2010s

Got: an oscilloscope card for IBM compatibles!
This thing is ancient, the specs are miserable and all it is, is this Analog Devices ADC with addressing logic and a few AD711 OP amps as a front end. But it's pretty damn cool.

This is what I got in exchange for the Philips scope.

Fixed: Philips PM 3355 hybrid analog/digital oscilloscope. Data acquisition board suffered damage from leaking capacitors, including a broken trace that took some diagnosis and circuit analysis to find. Oh and the power supply was bad, too. Oscillating frequency pulled into the audible range by a bad RIFA, that did not blow.