At school, three of us were interested in electronics, we were asked by an old lady to repair her radio, she did not like the new fangled transistor things, so we tried, but we could not find any valves, however we did find an old transistor radio on the tip, smashed, but worked.
So we set to hiding the transistor radio inside the old valve one, some new components like on/off volume control, and a new speaker to match ohms of transistor output, but we managed to hide the transistor quite well, told her she now needed to use a 9 volt battery instead of the 48 volt or what even it was, and she was very satisfied with the result.
Stopping me on the street to tell me how well it worked, and she had not needed to recharge the accumulator once since the repairs, and how much better the sound was to the new transistors.
We as said were kids at the time, so would that be called kidology.