Hi, Dennis,
One of the first things I would check, which takes only seconds, is whether the damper pedal is traveling too far. The setting for the Steinway damper upstop rail is difficult sometimes, as you mention, since you can get different results with the key alone versus key down with damper pedal engaged. Even on new pianos, I have sometimes found too much travel.
Ideally, when the damper pedal is all the way down, you should be able to play several different keys (including sharps) in bass, midrange and treble, and just be able to see the damper wink a tiny bit. If you see no wink at all, the pedal is traveling unnecessarily far, making it even harder to get the upstop rail down where it belongs. (Conversely, if you see way too much wink, the tray needs to travel more, and the pedal probably feels shallow.)
If that’s a problem, you can change the damper pedal trapwork lever stop (usually a block of firm white hammer felt underneath the keybed) by shimming it a little or putting in a thicker piece. That will stop the lever travel sooner. If the lever and tray don’t lift the dampers so high, you can set the stop rail lower.
Certainly other comments offer really good ideas. The amount of travel is sort of basic, something you can check super fast and fix easily, and at least get that part of the equation taken care of.
Kathy
Original Message------
Try putting cardboard punchings on the upstop rail screws, to move the rail as far forward as possible, close to the damper flanges.
I don't know if this will help on a D, but it has helped on smaller pianos.
If it doesn't work, you've invested 15 minutes to find out.
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Ed Sutton
ed440@me.com
(980) 254-7413
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