I have a Shires Q and I think my mini-balls are binding and jamming the linkage. I've oiled them just before playing last night and for some reason while playing the valve would not actuate. Usually it frees itself when I twist the part of the rotor it's connect to but that wouldn't budget either. Eventually they worked loose and didn't cause any more trouble during the rehearsal.

Is there a quick and easy way to pinpoint the blame on the mini-balls vs the rotor?

Thanks!

unscrew one of the linkages, and move the rotor.

Thanks, valve was fine. Important to oil both sides of the ball. Much better now.