So, again it's been working well, and another gremlin has popped up. Upon startup, the first digit reel from the right (ones), makes a loud buzzing noise and vibrates like crazy when it hits the 7. I checked the points on the unit and everything seems normal. If I manually roll it through to 0, then the tens reel does the same thing.
I swear this thing is cursed. Previous owners did some strange hacks that I've tracked down and repaired.