Petrov 125 IV noise problems

[J Patrick Draine]

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