Yamaha jumping jacks

[Annie Grieshop]

Howdy Ric, et al.,

The jack tops did appear to be unreasonably close to the butts, which I
wondered about.  And, yes, the double-strikes are a soft-blow phenomenon.
But I could feel the hammers wobbling when I played before starting tuning,
and I'm not about to leave customers with that, even if they'd never
recognize (or probably even notice) the wobble.  I thought the jack return
springs looked pretty puny, but maybe looks are deceiving in this case.

When did Alan deal with these issues in older instruments?  I haven't seen
any such reply to my query, so I'm wondering whether I missed something (as
usual <g>).

Thanks!

Annie


> -----Original Message-----
> From: Ric Brekne [mailto:ricbrek@broadpark.no]
> Sent: Wednesday, November 02, 2005 12:11 PM
> To: pianotech
> Subject: Yamaha jumping jacks
>
>
> Hi there Annie
>
> If these are new pianos, and the action is reasonably well regulated
> then my first guess is always too strong jack return springs and / or
> too strong damper springs.  Both tend to leave the jack top just a tad
> too close to the butt. A clue that these springs are involved is that
> the double strike goes away if you insure a very firm bottoming of the
> key stroke.
>
> On older instruments, lots of things can come into play. Alan delt with
> most of that nicely.  Tho I would add that  the jack stop rail on
> occasion can also need adjustment.
>
> Cheers
> RicB
>
> Annie Grieshop wrote:
>
> I had two tuning jobs yesterday that involved relatively new Yamaha
> verticals - an M500 and an M450.  Both have very jumpy jacks (or,
> at least,
> that's my analysis of why they're tending to double-strike, even when
> well-regulated), and I'm wondering why.
>
> Both have plastic jacks and synthetic buckskin.  The M500 had been treated
> with something that looked graphite-like and was less jumpy than the M450,
> which leads me to believe that the proper lubricant (or other treatment)
> might solve the problem.  I would very much appreciate any
> suggestions as to
> how to proceed.  Thanks!
>