Checking back in on this thread. . .
Rather than trying to fix my busted Nitty Gritty (for now, at least), I decided to purchase a similar (but less expensive) Record Doctor V, made by Audio Advisor.
I've only had this new unit for a few days, but it seems to work very well -- pretty much exactly like the Nitty Gritty did. I've said it before, but I think anyone who spins vinyl regularly should invest in a vacuum-type LP cleaner. They're well worth the cost. This particular unit is $200.
I'd accumulated several used LPs since my old machine broke. Listening to them "before and after" cleaning with the Record Doctor is quite a revelation. Clean records sound MUCH better.