Weird Tuning Pattern

[Zen Reinhardt]

Hi List!!

Ran into a new one the other day.  The piano in question is a Steinway L
(524174).  I had tuned the piano about every 4 months since it was
delivered just over 3 years ago ... nothing unusual when seasonal humidity
levels were taken into consideration.  However, this time, the piano was
pretty much at pitch in the lower end of the F3-F4 temperament section, a
little flat for the remainder of the tenor section, quite sharp in the
middle treble and absurdly sharp in the high treble.  The bass and the
first 1/2 octave of the tenor were nothing out of the ordinary for this
time of year for this particular piano.  Since this pattern was so weird
with the flat spot right in the middle of the piano and the high treble
being so sharp, I was afraid that something may have given out in its
superstructure.  I scrutinized the plate, the rim, and the beams looking
for any clues but could not find anything.  I'm sure there is something I
overlooked -- any ideas about what I might check for next?  Could something
have given way in the pinblock or bridge?

Usually when I come to this piano in mid- to late summer, the low bass and
high treble aren't too far off, the low end of the tenor is quite sharp at
the bass break but tapers off to being not-quite-so-sharp by the treble
break ... a typical high-humidity pattern.

Meanwhile I hope to keep close tabs on this piano just to see how it
adjusts going into the next season, to see whether or not it goes into its
typical mid-winter mode with the tenor quite flat and the extremities being
not as affected.

Any and all ideas and theories will be greatly appreciated ... THANKS! 

ZR!  RPT
Ann Arbor  MI
diskladame@provide.net