The problem I've come across with the "wholesale recap" process is when someone isn't recording what they are doing. Or how the thing looked before the "resto."
Then, after the recap, the stupid thing doesn't work or sounds like it's going to blow up or something. The unit ends up on the bench, with a box of spare new and used parts.
These are not fun fixes — that I will not do them anymore.
Makes sense, and I am hardly the most experienced, but when I find fusible resistors have drifted, I replace all of them. Certain units used known capacitors that tend to go bad, esp with heat like the blue Matsushita caps in Technics units. If you find one or two bad ones, you should probably replace all as they tend to leak as well. If everything tests within specs, no great reason to change parts that I see. And parts changes can cause other issues, like the difficult one to figure out that I had recently with a Technics unit where new transistors (replacing some blown ones) were much faster parts than the originals and were likely the cause of oscillation that blew up the RC components. Adding some capacitance in the right places fixed the issue, but some of these old circuits were designed quite specifically.
