Player piano vent block diagnosis

Greg Graham grahampianos@yahoo.com
Tue, 1 Mar 2005 20:46:41 -0800 (PST)


I wanted to call this subject "Players suck" just to
get some attention, but refrained.  Technically
correct, but often mistaken for a disrespectful value
judgement.

My problem:  customer's Laffarge upright player, built
1919, player action nicely rebuilt 1970, still very
clean and tight, works great, EXCEPT...

When starting a roll, there is the sound of a major
vacuum leak.  The spool turns slowly, but no keys
play.  You have to turn the electric vac up to full
power, something pops shut, then the piano plays
perfectly, even after slowing the vac back down to the
minimum.  The pump is tight, the motor is tight, the
action stack leaks only a little at the end gaskets.  

I think the action cutoff "gate box and vent block",
between the pump reservoir and action stack is
malfunctioning.  It appears externally to be exactly
like the photo in Reblitz's "Player Piano...", page
106, Illus. 6-17, third printing, 1986.  

I didn't have time to take it apart, but was hoping an
expert would have an idea why this valve would be slow
to close, needing very high vacuum.  Any advice? 
Quick fix?  Something else wrong?

Greg Graham
Closet player piano aficionado in denial
  


		
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