Pianos gone bonkers

[Richard Strang]

Sounds like a piano with this problem would be a total loss, unless it was
one of the elites, Steinway, etc. The U1 I saw the other day would not have
been worth a new sound board. Thanks for the info.

-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org]On
Behalf Of Alan Forsyth
Sent: Saturday, June 14, 2003 5:56 PM
To: Pianotech
Subject: Pianos gone bonkers


Hi list,
Richard Strang wrote:

>>>"the only sound it makes is, BONK! It sounds almost as if the
hammer is hitting wood, instead of the string. This is only in a section of
notes,">>

You will have to check the downbearing.

I am finding this symptom increasingly in 1920's uprights these days. The
most common area though is the beginning of the bass break where a floating
bridge is part of the design. Because the bridge at this point is the most
cantilevered, it takes the most leverage stress from the strings.

To quickly check the downbearing, loosen one of the strings in the affected
area just enough to release it from the diversions of the bridge pins, in
other words, let the string run straight across the bridge without it being
diverted by the pins. Then tighten up the string slightly and then check to
see if it actually touches the bridge. If it does not make contact with the
bridge, you have a problem and a big problem. It means the soundboard has
sunk and lost it's crown. Last week I checked out a bonking piano this way
and the string I used as a guinea pig was lying 1/8" off the bridge.

As for a quick fix, I don't have one, but any others who would like to
gamble their reputations and credibility are welcome to come forth with
their ingenious solutions.

Regards
Alan Forsyth.




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