Yamaha GH1

[Ron Nossaman]

At 09:09 PM 03/09/2000 -0600, you wrote:
>Dear fellow techies,
>
>Patient:		Yamaha GH1, 14 yrs old.
>
>Condition:	Treble bridge delaminating from soundboard and soundboard
>delaminating from rib #2 & 3 (approx. C5 - G6).  Downbearing barely
>detectable at all points along bridges.
>
>Symptoms:		None really!  Tone is relatively even throughout the scale,
>with good sustain.  No dead spots, buzzes or rattles.
>
>I presented the client with the following options:
>
>1.	Do nothing.  She enjoys the piano and apart from the obvious untoward
>appearance, the piano sounds pretty much the way a GH1 normally sounds.
>
>2.	Reduce tension across the scale and remove top 3 octaves of strings,
>use various wedging, clamping, screwing, gluing and or sorcery
>techniques to reunite the delaminated portions of
>bridge/soundboard/ribs.  The worry here is that this may result in a net
>reduction in the already barely detectable downbearing.
>
>3.	Put newfound soundboard replacement savvy (re: Brandon
>University/Bolduc soundboard seminar) into practice and slide a new
>board into place.
>
>Anyone ever see this condition on a Yamaha piano before?  Anything to
>add to the above options?
>
>Best regards to all!
>
>Stan Kroeker
>Registered Piano Technician


Hi Stan,
Too weird. I've met lots of cantilevered bass bridges that had parted
company from their aprons, but I don't think I've ever seen a treble bridge
come off a soundboard. Any obvious signs of past soakings from either
drinks, rain, or over watered plants? Residual fish food? Is the soundboard
coming loose from the rim? The thing that bothers me here is that there
just isn't room there for the panel to be up from the ribs, and the bridge
to be up from the panel, without creating an enormous string bearing
angle... unless either the ribs broke and went down, or the plate went up.
It looks kind of scary to me, and I would hesitate to attempt a fix until I
thought I was pretty sure I knew what I was looking at. Meanwhile, I'd
inform the customer, with appropriate explanations, pictures, charts,
caveats, and technical gesticulations, that it looks to me like an
unidentified structural failure in progress. Being an unidentified
condition, The customer could elect to either throw at it whatever money
proves to be necessary to identify and fix it, throw at it whatever money
it takes to repair the visible aspects that  are repairable, with no
guarantee that the cause has been addressed, or keep smiling, keep playing,
and ride the process to it's ultimate end... whatever that proves to be.
Probably not much help, but another opinion on the fire.

Ron N