Hi Jerry, Thanks for the follow up. Very interesting, not something I've ever run into. When a rod is set too far in, in my own experience, tabs will tend to catch on the round part of the rod and hang sporadically (or consistently). This without any problem like what you describe. I guess maybe it depends on the dimension of the blade compared to the rod. Maybe Yamaha uses a wider blade than others (I have next to no experience with the CFIII, beyond occasionally tuning one). In retrospect, it is obvious that your problem couldn't have been caused by excess friction or by weak or disengaged spring, as both of those conditions would have prevented a loud slap occurring, though they might have explained the hang-up. I suppose that the sound of tabs passing the blade might not bother some pianists, hence they wouldn't care enough to learn to do the fine- tuned timing thing between sostenuto and damper pedal. In loud passages, it wouldn't be too apparent, certainly not to an audience. Regards, Fred Sturm University of New Mexico fssturm at unm.edu On Jan 4, 2009, at 6:57 PM, Jerry Cohen wrote: > The problem was that the sostenuto rail was positioned > too far into the action cavity, so the blade had too much overlap. > If you > engage the damper pedal after the sostenuto is down, the blade could > not > rotate past the tabs when you release the sostenuto, because the > blade is > too close to the pivot points of the tabs. Thus the blade is locked > up until > you release the damper pedal. The loud slap was caused by two parts > of the > sostenuto pedal linkage suddenly coming back together.
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