Intermittent ZINGing Chopin on M&H 1923 model AA

[Dave Smith]

I installed a dampp chaser on a nicely rewhatevered  M&H AA circa 1923 which
just migrated to Florida.  Will  be going back to tune in a month or so.
Meanwhile, owner complains of a buzzing or zinging sound on G#6 which is
intermittant and only appears once in a while in a certain Chopin Etude.
Sure enough, no amount of my playing around with this or adjacent notes
caused the problem, but I did hear it when she played the Chopin.  Very
short ZINGing sound as if a small screwdriver momentarily touched the
string.  Damper felt looks normal.   Damper adjustment seems right.  I could
see nothing out the the ordinary, at least to my eyes.  I removed the action
and checked the damper wire screw for this note, it was tight.  I did,
however, notice that by manually lifting and dropping each damper lever, the
one for G#6 caused a more metallic  sound when dropped than did its
neighbors.  Could not figure out why.  Need to be able to fix this noise
upon returning next month.

I have read the archives on damper zing.  Dont think it is damper felt
problem in this case.  Wondering if loose damper lift flange or a flukey
damper spring maybe could cause this sound?  If so, the damper flange screws
on this model appear to be inaccessable, as they are vertical.  Looks as if
the entire damper assemply would have to come out just to check lift flange
screws.

It's likely I've missed some basic thingee that everyone else knows.  Hope
so!  I would appreciate any thoughts on troubleshooting this noise, as well
as any insight on how the damper lift flange screws can be tightened, short
of removing entire damper assembly.

Dave Smith
SW FL