Worried About the Grandfather Clock

When my parents died, we inherited their custom-made grandfather clock.  I've always loved its chimes' mellow sound, but now the clock is ... well, sluggish.  It sounds like it's on 'ludes.  Or else smokin' dope, neither of which is remotely possible - a wooden clock would naturally be afraid of fire and clocks do not have mouths with which to ingest a Qualude. 

A mystery.