I have a fairly new Arca Swiss B1 ball head, and the knob that controls the pannning has failed in the middle of an extended photo shoot in Vermont(of course). There is a little screw at the end of the knob and it has broken off into the collar in the head that apparently stops the head from panning around. Is this a user repairable problem, or does it have to be sent back to Arca
Swiss or somewhere else.
BTW, is this a common failure with Arca B1 heads?