From Richard Brekne <Richard.Brekne@grieg.uib.no>
Sounds familiar alright... and it can be a difficult thing to track down. A few
hints that might be of help, tho your discription of the noise could point to just
about anything really.
Check the bridge notching to make sure that strings have plenty clearance moveing
off the bridge from any and all possible contact with the bridge.. especially along
the side of the right string.
Also check to see if there is any chips of wood laying jamed around in the string
area. As far as the dampers go... the usual stuff applies.. make sure the system is
regulated correctly with the pedal pulling the dampers out just a tad more then the
depression of a key will, and make sure the stop rail is screwed tightly in place
and that its not to far in. Also check the screws that hold the letoff button rail
in place, and that this hasnt moved around any. Also check the damper lift rod
hinges.. probably not the problem but its worth a check.
>From the sounds of things something is contacting the strings when they are allowed
to really vibrate at full amplitude. I even saw a Petrof come in once that had the
damper system regulated such that the lower end of the damper lever was so close to
the strings that many of them would actually contact the strings when the key was
depressed... lovely regulation stuff..
Good luck and drop another line when you have solved it, or need some more thought
bouncing.
Grin... Wim of course doesnt have to deal with these Petrofs... for some strange
reason all of the Petrofs that come into his store are in perfect condition and are
almost as good as the best of European pianos for a quarter of the price...
sorry Wim... couldnt help myself... all in fun... besides... I know why you like
them.. they do have a pretty nice overall sound.
J Patrick Draine wrote:
> Dear Petrov experts:
> I have a customer with a new (3 months old) Petrov 125 IV, their 49"
> upright. I tuned it in June, shortly after delivery. He called
> yesterday complaining about annoying rattly action noise. My
> diagnosis based on the phone call was loose hammer flange screws, or
> even perhaps loose glue joints between the hammer/shank/butt -- but
> that was incorrect.
>
> I dropped by late in the day with just a few minutes to spare before
> heading home in time for various family activities.
> The noises are apparent mainly when the damper pedal is engaged and
> the piano is being played fairly vigorously. While we can isolate a
> few target source notes they don't generate much noise unless all the
> rest of the repetitive r&r/Bruce Hornsby/stride piano chording is
> going on at the same time.
> If it were a grand I'd suspect damper wires vibrating slightly
> against bass strings -- but it's an upright.
> I *did* tighten the hammer flanges, damper heads, damper flanges of
> the (suspected) source notes, but they were already firm, and no
> improvement occurred.
> The pedal dowels were the next suspects: the plastic/metal
> pins/rubber contacts between the (aluminum not wood) dowels had
> excess free play -- BUT installing a better bushing didn't help.
> Is there something potentially funky about the damper lift rod
> bushings? I didn't have time to pull the action, but still managed to
> get home late & have the family ticked off at me.
> The customer bought the piano in NYC to save $2K compared to the
> local dealer; the local dealer won't give him the time of day now, so
> dropping the problem on the local dealer isn't an option.
> Besides, it *should* be the sort of thing that goes away with a few
> tightened screws, etc.!
> Richard B, Wim, et. al. -- does the problem sound familiar?
> I'm going back on Tuesday with less time constraint, and hopefully your advice.
> TIA,
> Patrick Draine
> Billerica, MA
--
Richard Brekne
RPT, N.P.T.F.
Bergen, Norway