Mysterious blocking notes

[Jim]

Dear Aaron:

How much clearance is there between the hammer tail and the backcheck
when the hammer is on its way up?  How much clearance is there between
the neighboring hammer flange center pins?  Could there be a loose screw
lying inside a wippen which may at times contact neighboring wippens?
Or is there a loose keylead which at times may touch a neighboring key?

Jim Coleman, Sr
..

On Wed, 18 Dec 1996, Aaron Bousel wrote:

> List,
> I've sent this twice in the past two days.  Hoping it will go through now.
>
> I have a customer with a S&S 'M' with an elusive, mysterious action problem.
> First some background:  It is serial number 490934 built in 1984.  The
> action is cloth bushed, except for a Teflon plug that holds the repetition
> spring in place.  It has those screws with the reduced and knurled bodies
> (just below the head) that sometimes break.  (This is irrelevant to the
> problem, but might help someone identify the action.)
>
> The complaint is that, on occasion, apparently at random, certain keys won't
> go down.  Or more precisely, they will go down but require an additional
> amount of force to start them.  Typically, he will be playing a passage and
> the note or notes resist his touch.  If he stops and goes back to those
> notes, they seem to work fine.  Needless to say, the piano smelled me coming
> and played fine when I tried to duplicate his experience.
>
> As he found the problem to be worst on notes C-52 and D-54, I began my
> investigation there.  The only thing I noticed that was different about the
> action parts in that area was that the wippens seemed too far forward, i.e.
> the capstan had worn the wippen cloth very near the back of its length, and
> the jack tail was hitting the let-off button very near the front.  I checked
> all pinning, lubed jack tops, and generally went over these two notes with a
> fine tooth comb.  I used travel paper on the wippen flange in order to move
> the whole wippen back just a bit.  Put it back in, and of course it worked
> fine.  But, it worked fine for me before, so I had no confidence that
> anything I'd done was of any use.  Tuned the piano and while checking it out
> after the tuning, I THOUGHT I felt a bit of resistance on G-47.  Going back
> to the note, I couldn't reproduce the sensation.  At this point I had to
> leave so I explained that I'd tried some adjustments and as I was coming
> back in two weeks to tune his upright, I could look into again at that point.
>
> Two weeks later he said it seemed much better, but G-47 stuck on him--once.
> G-47 didn't exhibit the same alignment problems I saw at the end of that
> section with C52 and D54.  I did everything to G-47 I had done to the other
> two notes, except shimming out the wippen flange.
>
> That was a month ago.  I just got off the phone with this customer and he
> said that just last Saturday A-49  'blocked' on him.  He went to the
> Steinway dealer here, who has sold him a Dampp-chaser (which I've been
> trying to do for awhile now) but I doubt that this is a humidity problem.
> For the moment he's going to let the Dampp-chaser work for awhile and see
> what happens.
>
> The sensation I felt was as if someone had pushed a tri-chord damper just a
> bit down into the string and then tried to play the note, an initial
> resistance, then it lets go.  I don't think that it has anything to do with
> the dampers, that's just a good description of what it feels like.  You may
> have noticed, as I did that it only seems to happen on the naturals.  I
> checked out the keyboard and everything looks fine, keys moving as they
> should, not chucking.
>
> Has anyone ever come across this before?  I would sure be great to be able
> to come back to this guy with something concrete.  Thanking you all in advance.
>
> Regards,
>
> Aaron Bousel
> Ormstown, QC  Canada
> abousel@rocler.qc.ca
>
>