I just bought a replacement pinch roller from Athan in SF for my 5050 B3 1/4" machine. It came today and it is much larger than the original roller, with just enough gap between the capstan and roller to fit the tape. Also, when I replace the cap on the roller with the original one and tighten down, it prevents the roller from turning. Seems to work fine without the cap. Is this right? Thanks, Larry