Hi guys, I picked up my first TLR off Ebay last week and I bought a Rolleicord III with a known issue with the film advance knob.
It's not a deal-breaker, but it's slightly annoying.

Film loads fine and the advance is "grindy" (i.e. feels like metal on metal) but not an issue. The issue comes on certain frames when you have to depress the center button the advance knob multiple times. You press it, turn a little bit, press it again, turns a bit more, and repeat a few times before it returns to normal and lets me advance to the next frame. The worst of it happens at frame 7 or so.

Anybody knows what is going on? As I said, it's not a deal-breaker for the price I paid, but if it's an easy fix, I'd love to know.