<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> <body bgcolor="#FFFFFF"> Often enough this description fits the heavier hammers in the bass area, but sometimes well into the middle section. Good regulation is of course a prerequisit, but also you will find that loose centers, or centers with uneven bushings will cause this problem. Also if the hammers are not hitting the strings squarely you can experience this. Worn (as in almost polished) checking leather is another culprit as is the same situation with the tails themselves, but you have roughened them already. Backcheck height can be pretty high, but probably no higher then 10mm, preferably a bit more. Repetition springs can contribute, but then that kinda comes under regulation. You need a nice solid (as in definant) rise upon release, but you shouldnt feel much of this spring upwards in the key. Another biggie is the height of the backcheck itself, and / or the length of the tail. At drop with the key fully depressed but the hammer not in check, the top of the backcheck should be just about the same height as the bottom of the tail. I personally like it just a tad higher, but standard practice is about 1-2 mm below.   Tom Driscoll wrote: <blockquote TYPE=CITE><style></style> Fellow Techs< Seeking advice on checking problems encountered when regulating older steinway actions> (Assuming backchecks not worn)< Roughing tails has helped,  angle changes of the backcheck to steinway service manual diagrams helps also,but I still can get some hammers bouncing off the backcheck.> <Balancier springs are not too strong>Raising the height  of the backcheck seems to be the most  effective> Should I consider replacing backchecks with a taller profile part?  old wires replaced also or new backchecks on the origional wires?> Thanks for your responses>< Tom Driscoll></blockquote> -- Richard Brekne RPT, N.P.T.F. Bergen, Norway   </body> </html>