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MMD > Archives > May 2002 > 2002.05.18 > 02Prev  Next

Universal Player Piano Tubing Problems
By John A. Tuttle

In my continuing effort to help both technicians and the owners of
Universal player pianos made in California, today I'm going to address
a few problems involving the tubing.  Each of the problems has been
found at least three times.  To me, this indicates that these are
common problems.

First, the trackerbar tubing, specifically, the tubing that runs
from the trackerbar to the manifold in the keybed.  For those who don't
know, the tubing runs between the keys.  They are hollowed out like
this )( near the fulcrum, or balance rail pin.  The spoolbox is
elevated about two feet above the keys.

The most common problem involving the tubing is that it sags or 'weeps'
as it ages.  Because of its proximity to the backchecks (part of the
piano action), it often makes contact with the backchecks, pushing them
forward (or towards the back of the piano).  When this happens, the
effected note cannot properly reset.  Most typically, the indication is
that the note 'mis-fires' or strikes the strings very weakly.  Also,
because the keys in this section are lighter at the back, the key dips
down ever so slightly in the front.

The easiest way I've found to correct the problem is to weave some
vinyl trackerbar tubing in and around the areas above and below the
area where the backchecks are located.  Then secure the ends of the
lines to the underside of the spoolbox platform, pulling all of the
tubes closer to the front of the piano, and away from the piano action.

The second easiest way is to attempt to push the tubes further onto the
nipples, which are between the keys.  My only concern about using this
method is the possibility that the position of one or more of the nipples
might change if the tube isn't pushed perfectly straight down.  If the
nipple did get bent or forced out of position, the tube could easily
make contact with the side of a key, causing drag or "a sticky key".

The second problem related to the trackerbar tubing is about tubing
that "falls off".  Well, it doesn't really fall off.  It is actually
being pulled off.  The problem is that the tubing was cut too short.
The solution is to install short lengths of tubing as necessary.

But I have a question: Why is the tubing creeping off?  If it's being
stretched to the point where it will eventually come off, why does it
stay on at all?  And what forces are at work that eventually pull the
tube off the nipple?

Well, on to the last of the tubing problems, which involves the main
supply tubing and auto sustain tubing.  The problem is that the tubing
cracks where it is connected to a fitting.  The solution is to replace
the cracked tubing.

To the owner, the indication that this problem is developing is a slow
loss of volume over a period of less than a year.  In the extreme, the
player unit will just stop coming "On".  It will seem like it's trying
to come on.  The roll might even roll forward, but the music won't
play.  Or, it could look like the music is trying to play, but the
hammers aren't actually hitting the strings.

To the technician, a quick physical exam will tell all -- and note that
I did not say a visual exam.  The crack could be on the backside, where
you can't see, so tug on them.  Bend them around a little.  That way
you can tell if they're loose.

This is another problem that poses a question.  Why does the tubing
crack?  From all appearances, it doesn't seem old enough to be
cracking.  Also, it doesn't seem to have to stretch very much to get
over the fitting.  However, it does stretch a little.  So, how much
stretch is too much?  Could there be other factors at work here?

There is a bit of a difference between the supply vacuum fittings found
in the Universal player action as compared to those found in a circa
1920s player piano.  The Universal fittings are mostly plastic, and
the ones that are brass are quite long.

Addressing the plastic first, I've noticed that the tubing is much
harder at the point where it contacts the plastic.  Just one-half inch
away from the fitting, the tubing is relatively supple.  Occasionally
there is a gooey, sticky substance at the connection point.  I can only
assume that there is some chemical thing going on between the tube and
the fitting.

Addressing the long brass fittings.  These fittings are at least one
inch long.  The folks at Universal almost always pushed the tubing all
the way onto the fitting.  This makes removing the tubing very difficult.
My recommendation: If you have to remove the tubing, replace it!  Don't
even bother trying to save it.  Slice it open at the fitting, pull it
off and throw it away.  Chances are it would have cracked open on its
own in a few more years anyhow.

If you insist on trying to remove the tubing, try pushing it further on
first.  Try hard!!  Then, using a wide-blade screwdriver, pry under the
edge at the end.  See if it gives.  Then go to the opposite side and do
the same thing.  The point is to loosen the tubing from the end first.
If you simply pull on the tubing, the chances are great that the tubing
will rip (or break) apart even if it is relatively supple.


John A. Tuttle
Brick, NJ, USA

 [ The liquid weeping or seeping from vinyl hose is the unstable
 [ plasticizer, which is an oil like either kerosene or banana oil.
 [ I suppose that the oil also seeps between the hose and the nipple,
 [ destroying much of the static friction which holds the hose to
 [ the nipple (plastic or brass) when the hose is stretched during
 [ installation.  The vibration of the piano playing is enough to
 [ wiggle the stretched and oiled hose enough that it slowly crawls
 [ off the nipple.  -- Robbie

(Message sent Sat 18 May 2002, 14:55:41 GMT, from time zone GMT-0400.)

Key Words in Subject:  Piano, Player, Problems, Tubing, Universal

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