I was taught that you should keep pulling things out of your bag-o-tricks until something works. The thumb tack idea is a great temporary fix that I'll add to my bag. However, Bruce mentioned that this was a long term problem, so it deserves a long term fix. There was no mention of where on the rail the knock is coming from. Because of the thumb tacks, we assume the front rail, but is it the sides or the mid section? If it is knocking at the sides, it could be due to the fact that the key block action guides are not pressing down on the keyframe guides. It was wise of Bruce to be wary of creating further damage but those guides are designed to have slight pressure and until they do, you cannot isolate the problem. I would contact Kawai and ask Don if there is a way to make that adjustment to the key block action guide before I tried anything else. Phil Glenn National Service Manager Young Chang Acoustic Pianos (800) 874-2880 x110
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