Success! My $50 Craigslist washer/dryer set is functioning perfectly (well, the dryer is really loud due to what sounds like a wobbly bearing, but it's functional, and whaddaya want for twenty-five bucks??).
This was the first actual improvement I've made so far. Everything else has just been refurbishment, i.e. replacing broken bits and cleaning. This is new functionality. It makes me inordinately proud.