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MMD > Archives > July 2009 > 2009.07.23 > 04Prev  Next

1970s Aeolian Player Piano is Leaking
By Pete Knobloch

Victor Wolfe states that he has a 1980s Aeolian player with a vacuum
leak problem.  He thinks it is due to leaky valves.  The valves might
be a good guess but, because the reservoir collapses entirely when
the pump is turned on, the problem might be elsewhere.  The first two
things that I would suspect would either be the stack cut-off valve or
the eighty key pneumatics are hard as a rock.

The first thing to check is the stack cut-off valve.  Remove the roll
from the player, press the power button and hold it in with your finger
so it won't turn off.  Listen to the sound that the vacuum motor makes
and try to ignore the noise of the roll transmission air motor.  Now,
with the other hand, force -- and I mean _force_ -- the Play/Rewind
lever into the Play position.  You should hear all sorts of leaking air
and you might detect that the vacuum motor slows down slightly.  This
is normal and means that the cutout valve is working.  You will also
notice the reservoir opening up.  If the noise doesn't change and the
reservoir stays tightly closed, then the problem is in the stack cutout

Now that you know the stack cutout is working, check how stiff the key
pneumatics are.  With power off, use your fingers to manually close
a few of the pneumatics found at the bottom of the stack.  It should
not take any effort at all to close the pneumatic that drops the key
and plays a note.  If you hear crackling sounds or if it is difficult
to get a note to play, then this means that the rubberized cloth needs

These newer Aeolian players are 30-40 years old and are ready for a
rebuild.  The most common failure is the pneumatic cloth turning hard
and cracking.  I also suspect that these pneumatics were hinge bound
from the factory due to how they applied glue to the hinge.  Hard cloth
can also be detected by playing a roll and noticing that the keys don't
drop enough to play, or the piano plays softly with a lot of missing
notes.  It looks like the problem is the lack of vacuum but the real
problem is that the vacuum can't close the pneumatic due to the extra
effort needed for it to close.

The plastic valve used in these players were cheep to make and fairly
inefficient, even when new.  Most of the customers would load a roll
and push the "On" button and listen to the music.  "Who cares about
how hard it is to pump manually," the salesperson would say.

I have even seen some of these players with the original cardboard
tacked on the front of the pedals.  When I exposed the pump pedals to
the customer, they replied, "I didn't know about those things."

Pete Knobloch

(Message sent Thu 23 Jul 2009, 21:50:04 GMT, from time zone GMT-0700.)

Key Words in Subject:  1970s, Aeolian, is, Leaking, Piano, Player

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