yamaha broken strings

[ignacio lopez]

I have been reading the pianotech list now for a month or so, and really
enjoying it.  I am working in the conservatory of music in Tenerife,
Canary Islands, Spain,and have very little opportunity to talk to other
technicians, so being connected to the pianotech is great.  Though I have
lots of questions, I would like to have some feedback on one particular
problem I am having now.  We have 5 Yamaha C5 grands, and one (F5091975)
has begun breaking strings (always at the capo bar) in the top treble
section (5 strings during the past 5 weeks). The strings are original and
not oxidized, the shape of the capo bar seems ok, piano is at 440, hammers
are worn (about 1 cm flat on strike). Any ideas on why the strings are
breaking?  Anyone have the phone number for Yamaha in Japan?

Looking forwards to your input.  Mary Logue