[pianotech] Damper Puzzled

[PAULREVENKOJONES at aol.com]

That isn't a puzzler, it's an mystery inside of an enigma. Unsolvable  
without being there. 
 
P
 
 
In a message dated 3/6/2010 1:22:32 A.M. Central Standard Time,  
defaziomusic at verizon.net writes:

Barbara wrote:

|Well, Joe, what was it? 



|Barbara Richmond, RPT 

|near Peoria, Illinois
Joe writes:
Hi Barbara - thanks for asking. 
It turns out that a small quantity of liquid had
spilled inside the action cavity, and had landed
on the damper tray felt, right under the two 
damper underlevers in question. It had made the
felt hard just under those two underlevers. 
As is normal, there was lost motion between 
the tray felt and the underlevers. When the
tray was set in motion, it had enough inertia 
and hardness to launch those two underlevers 
forcefully. Since all of the bushings were 
slightly worn, the extra " oomph" was enough 
to cause the damper felts to pluck the strings. 


I needled that small area of the damper tray 
felt, and the two problem notes then behaved 
exactly like their neighbors. 
Joe DeFazio
Pittsburgh (er, Baltimore at the moment) 
 



----- Original Message ----- 



|Here is a puzzler I encountered last week. Someone may get it right away, 
but it took me some head scratching to figure out, and I had never seen it 
before: 





|The piano was a circa 1930 generic little american grand. I was called in 
to repair the lyre (the regular tuner is blind and does not do that type of 
repair work). Of course, assessing damper function was part of the job, and 
it was reasonably OK except for the puzzler: 





|Whenever I depressed the sustain pedal (after repairing the lyre) two 
adjacent bass bichords sounded, as if they had been plucked. However, when I 
reached inside and lifted either or both of the underlevers by hand, there was 
no plucking sound. 





|Just to rule out some things, the underlever leads and flanges were tight, 
the guide rail bushings were worn but not terrible, and the damper wires 
were not touching or almost touching the strings. The damper heads and felts 
were not interfering with their neighbors. The damper felts were old, but no 
more so than their quiet neighbors. There was no sostenuto mechanism. That's 
where I was when my head scratching commenced, as shall yours, if you're in 
an itchy frame of mind. 





|Joe DeFazio



 



=
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