Diagnosis:
Disconnect the spring on the G# key, so that it does not contact the key in any way.
Press down the G# lever.
Check whether the G# key moves completely freely, i.e fast operation under gravity alone.
If not:
Disconnect the spring on the G# key, so that it does not contact the key in any way.
Press down the G# lever.
Check whether the G# key moves completely freely, i.e fast operation under gravity alone.
If not:
You have a problem with excess friction associated with the hinging system. Remove the key, and check whether the rod is completely free in the tube.
If so:
If not:
If so:
Check that there is sufficient space between the posts for the key to fit easily. Also put the hinge rod alone through the unthreaded post and ensure that it lines up accurately with the threaded post. Also check that the rod screws in easily into the threaded post; otherwise suspect that this post is out of alignment, twisted, and when the rod is screwed in tight, the rod may become distorted.
If not:
Clean tube and rod of oil/grease/muck/varnish/rust, and then check whether the rod is completely free in the tube, i.e it falls through under gravity.
If not:
If not:
Straighten parts appropriately.
