<HTML>Carol,         I am only a rookie out of piano t= ech school, but possibly the center pin bushings in the hammer flanges could= be swelling (due to humidity) and this could be causing a "drag" if you wil= l, making center pins' tighter, the motion stiffer, hence, the keys harder t= o depress, and shows up interpreted as a heavier weight. I am guessing a clu= e would be how fast (or rather sluggish) the hammers return to their rest ra= il or pads. Julie Gottchall, Reading, Pa  </HTML>