Many thanks to John Tuttle and Wayne Lincoln who replied to my request
for help on my player piano tracking device.  I removed the left-hand
roll chuck and cleaned it out with solvent as John recommended, and now
the piano runs perfectly.  My family and piano students can now play it
normally without my needing to fuss.  I salute our editors and music
community for your generosity - our concerns for the future of the "hobby"
are bountifully addressed by the activity going on right here at MMD!