Disklavier

It has been quite a while since I last posted to the Disklavier file
swappers group.  (Where does the time go?)

Unfortunately for me, my reason for this post is to solicit opinions
about what is wrong with my piano and perhaps how to fix it myself.

I have had my 5"3" playback only DGP1XG grand Disklavier since
mid-1999. (I had to look in my database entry here on this site to
make sure!)  I have had it tuned once or twice a year and have had
good service after initial glitches in the solenoid mechanisms were
taken care of under warranty.  

A few days ago I began to notice a distinct reedy rattle or clicking
noise when I (or the solenoid) depressed the G3 key (G above C3). 
This G key produces the loudest noise; however the noise also occurs
with vigorous operation of one or two keys below and above the G,
lessening with the distance from the G. The noise seems to originate
under and perhaps slightly behind the keyboard. It leaves me with the
impression that something is loose or out of position.

I would be grateful for any self-help suggestions for this problem. It
would not seem to be a solenoid problem -- the noise occurs when the
piano is played manually as well as when it is playing under program
control. 

I realize that I am due - probably overdue - for a "major" tuneup and
regulation by a Yamaha technician. For budgetary reasons, I am trying
to defer that for a few more months.  In the meantime, have other
users experienced - and fixed - similar problems?

Thanks for any suggestions.

Mike McGregor
Lockhart, TX