Yamaha C7 Pinblock Fit

[David Ilvedson, RPT]

I had a stability problem with a Yamaha C7 and ended up taking the tension
down a bit, applying pressure below the block and tightening the
plate/pinblock screws.  They turned a 1/4 turn and the piano has be stable
since!

David I.

----- Original Message -----
From: <JIMRPT@AOL.COM>
To: <pianotech@ptg.org>
Sent: Thursday, January 11, 2001 2:42 PM
Subject: Re: Yamaha C7 Pinblock Fit


> Whoa Todd!
>
>  <<"Sure enough - huge gap in">>
> the treble section between the plate and pinblock.  His question:  Would
> it be worth his time and their money to try shimming the pinblock?">>
>
>  Are you or your friend sure this is the cause of any tuning instability?
> Since we are speaking of a C7 the pinblock is screwed and glued to the rim
> and is mortised/glued into the stretcher...are you, or your friend, saying
> that a "gap" in the treble section flexes and causes this apparent
> instability? If so what evidence is there that this is what is actually
> happening? What are the conditions in the church? Is the climate control
> system on all the time? are there midweek services in the church? Is there
a
> DC system on the piano?
>
>  Something obviously is happening to this piano judging by your friends
> remarks but.......I seriously doubt it is due even partially to some "gap"
in
> the treble section of the pin/flange fit. There are Yamahas out there
which
> have 'no' flange to pinblock contact and are perfectly stable or at least
as
> stable as any comparable make.
>
>  The supposed "treatment" of the block is an entirely different matter but
> again is not needfully the cause of any "instability". Although this
> "treatment" of the block would cause me to replace it if the pins were
loose
> I would not think that the "treatment" in and of itself is cause for
> replacement.
>
>  I think that much more information is needed in this case before an
educated
> evaluation can be made.
>
> <<"If someone
> competent had seen it early on, it could have been fixed by Yamaha at
> their expense and saved this church tons of money in tuning fees over
> the years.">>
>
>  There seems to be a leap of faith that no one "competent" has ever seen
this
> piano...do you know that to be the case? In addition there seems to be a
leap
> of faith that the piano needs to be fixed, should have been fixed by
Yamaha.
> Again this is not needfully the case and probably isn't.
>
>  Until there is some hard evidence that this "gap" is what is causing the
> "instability" problems then I would be very cautious in saying that this
is
> 'the' problem.   If he wants to address the "gap"......... then driving
some
> wedges up between the flange/block interface will tell very quickly
whether
> the 'real' problem is at that point. This needn't be a costly or time
> consuming procedure for anyone.
> My view.
> Jim Bryant (FL)
>