This is an update on the sostenuto issue. I found some excellent articles in past journals with good illustrations and procedures. Bill Spurlock had a 3 page technical with great diagrams and explanations, Susan Graham had several pages of great information on pedal regulation and Maria Pollock sent me some good tips. Thanks to the search feature that Jason Kantor created it is much easier to find journal articles on just about anything. One big takeaway was that the procedure for Steinways is different so it pays to read up. Anyway this was a Yamaha and fairly straight forward. With the action out I sat on the floor and worked the damper pedal and the sostenuto pedals by hand and performed various tests. I could visually follow the rotation of the blade and with my Ryobi inspection scope I could see where the blade was set and its angle. I tightened different screws on the brackets to snug them up With the action back in and cheek blocks screwed down I tested everything and found that it took a little more effort to get the sostenuto blade to rotate. I think I was guilty of not apply enough foot pressure but in the end I took out the lost motion that was in the una chorda/left shift pedal, tightened some screws on the pedal trapworks, tool out some of the lost motion in the damper/sustain pedal. Adding some pro lube spray on the keybed helped the action to slide to the right and back .
I will probably revisit the issue to put some new felt on the brackets that connect the pedal to the blade. Seems it could be snugger because it slides a little to the left from the torque
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James Kelly
Owner- Fur Elise Piano Service
Pawleys Island SC
(843) 325-4357
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Original Message:
Sent: 10-11-2022 16:30
From: James Kelly
Subject: Yamaha C6/C7 sostenuto
I am prepping a Yamaha C6/C7 grand for an upcoming concert Thursday. I always test the pedal operation to insure there are no squeeks, groans there is no lost motion in the left una chorda, there is proper lift and lm in the right sustain and that the sostenuto hold up the dampers for specific note holds them all up when the sustain is played and the sos is pressed etc. Today no matter what I did the sos did not hold the tabs. Didnt have time to troubleshoot much but slid the action out and saw that the blade rotates. I am thinking screws have worked them selves out and I just need to snug them up but maybe there is a broken bracket. I noticed that the middle pedal rod contacts a cast iron bracket which is connected to vertical metal rod that goes through the keybed to the sos blade rail. This vertical rod is threaded and has two nuts - one under the cast trap lever and one above.
What function does this serve ? what angle should the blade be at when at rest and when fully engaged ? I am hoping it is a quick fix When I return in the am I will have the action out on my Edwards action dolly and it will be easier to troubleshoot.
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James Kelly
Owner- Fur Elise Piano Service
Pawleys Island SC
(843) 325-4357
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