I've been really getting to grips with harpsichord maintenance.  My
instrument has been a real pain in the neck in its first nine months,
but Polyanna-like I can say this has at least had the advantage of
forcing me to learn the ins and outs of repair quickly. Many thanks
to the list for tacit and active encouragement and help. I now have it
regulated--a happy state it has only achieved for a few days up to
now.  This made life so much easier I began to suspect some of
my deficiencies in playing weren't due solely to bad technique. I
discovered several keys no longer obviously sticking, but hindered
enough to make trills difficult, and several slow hangers.  Most
have responded, but there are still about 3 that have improved only
to the extent of hanging one time out of ten instead of one time out
of five. (If it likes the weather one time out of twenty.) The worst
offender finally gave in to a ridiculous lengthening of the jack pin: of
course now the damper leaks and the note doesn't stagger. I've
tried: changing or cleaning plectra, adjusting springs, restricting
tongue movement with a thread around it, adjusting height and
angle of dampers, and last resort, usually cautious change of jack
height.  This routine worked for most of the offenders.  Is there
anything else to do?  A little extra weight on the jack? Sacrifice a
black chicken?
I also have one key in particular that comes down with a thunk all
too often. So I suspect the problem is partly mechanical.  The
keyboard is very simple: pin in front, pin in back, whole thing
comes out like a tray. Is it just me or is an adjustment possible?
Thanks,
Jenny