Mystery Noise

[Avery Todd]

David,

   Have you checked to see if the upstop rail felt is there for that note?
And that those screws are tight?
   Another possibility. Because of the worn guide rail bushing, could the
damper wire be touching the string when played?  Just some guesses.

Avery

>I have a mystery noise that is baffling me and irritating my customer.

>The mystery noise is like a rattle, and is located in the first note past
>the bass/treble break - note A#2.  Although the overall "noise" level of
>this action is rather high, this particular noise ("rattle") is not in the
>key, wippen, hammer, shank or flange.  The noise is not from the soundboard
>or ribs or any loose case parts.  After inspection with a small mirror and
>light, there does not appear to be anything laying on the soundboard that
>would make a rattle like this.  The noise is isolated to the damper
>underlever, wire and damper head.  The damper underlever flange screw is
>tight, the screw that secures the damper wire into the underlever is tight,
>and the damper wire is tight in the damper head.

SNIP

>One other possibility:  This note right past the bass/treble break has the
>damper head offset quite a bit because of the plate strut. The damper guide
>rail bushing is worn out and the wire has a lot of loose play.  The damper
>head and wire do vibrate quite a bit when the key is played, but the rattle
>is not caused by the wire or damper head touching the plate, the adjacent
>damper head and wire, or any of the strings.  I do believe that the noise
>is coming directly from the contact of the damper wire with the worn out
>guide rail bushing.  Lubricating the damper wire has little to no effect on
>the noise.
>
>Question:  Is it possible to rebush an individual damper guide rail bushing
>with the rail still in the piano?  Removing the guide rail and rebushing
>the entire rail is out of the question because of the quality of the
>instrument.
>
>Suggestions are welcome, and will be forwarded to my customer who is also
>on the Internet.  If you don't want your answer forwarded to my client,
>please let me know and I will respect your privacy.
>
>Thanks for your help!
>
>David
>
>David A. Vanderhoofven, RPT
>Joplin, Missouri, USA
>e-mail:  dkvander@clandjop.com