misfiring jack

H. Pengelly pengelly_pensione@telus.net
Wed, 6 Dec 2000 21:01:32 -0800


Dear list, I recently tuned a Homer upright spinet that had a few
miss-hitting keys. Upon closer inspection I noticed that the jack wasn't
slipping back under the hammer butt. The key bushings are fine and the lost
motion is set properly and the problem persists. Incidentally the action is
miniature and the keys from the balance pin bushing are cut at a slope to
clear under the wippens. It appears to me that the back of the keys are too
light and sit up too high thus preventing the jack to return. If you press
lightly down on the back of the key then the jack goes back. There are no
weights in the keys and they are quite front heavy. When the soft pedal is
depressed the problem is worse. The front of the keys dip as if the bridle
tapes were too tight but they aren't. The weight of the action seems too
light  to stop the keys from rising up at the back. In my 16 years of tuning
this is a first for me,I know I've been lucky, and it has me perplexed. I
could probably fix it by adding weights to the keys but it originally worked
ok so what are your thoughts? Much appreciated
John Pengelly




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