Greetings all,  I'm in the process of installing one of Player Piano
Company's deluxe electric suction units.  It has a post that controls
the speed of reroll and a radio-like knob that adjusts the volume
during play.  Normally, the reroll is set first and then the volume
can be adjusted within a wide range.

I tried it out as I installed it and have found no difference.  In
other words, the volume knob does not work.  Am I missing something?
Is it an electrical issue?

Jeff Davis, Seattle (the home of on-shore flow!)