My Nakamichi tape deck died, and so I got a replacement belt and idler wheel tire for it. That didn't fix it. Internet searches suggested that corrosion in the cam motor was the most likely culprit.
Today I took it apart, opened up the cam motor, used a wire brush Dremel attachment and some Deoxit, and got it cleaned up. Put it all back together and it actually works! It was a frustrating process, with lots of tiny little parts, but gosh it's nice to have a functioning tape deck again.

