Hello MMD.  Almost three years ago, I began a rebuild of my Steck
upright Half Duo-Art.  At last it is starting to come back together
again.  A couple of days ago I had the upper action re-assembled and
re-tubed, or so I thought.  At least a run with a test roll and a
vacuum cleaner operated through a Variac autotransformer demonstrated
that all 88 striking pneumatics were operating.  The testing of the
other features of the player will have to wait until the lower action,
all rebuilt, is re-installed.

When I re-tubed the upper action I was very glad that I had made
extensive notes about which tube went where as I pulled the old tubes
out.  But they weren't quite extensive enough.  I've noticed that there
is one nipple on the Duo-Art On-Off switch that lacks a rubber tube.
My action has the pair of ganged wooden slide switches that are located
on the outside of the left hand spoolbox wall.  It is the rearmost
(when observed from the front of the player) of the four nipples
underneath the Duo-Art that lacks a tube.

The only time that the top end of that tube is closed to the atmosphere
is when the slide switch is in the Duo-Art position.  There are no
vacant nipples available anywhere else on the upper action; nor are
there any vacancies on the junction block that carries tubes down to
the lower action.  So perhaps a tube from this nipple is meant to be
teed into another line?

I have a Half Duo-Art tubing diagram issued by the British PPG, but
this displays the rotary switch that was installed on many British
models.  I have stared at it for some time and came away before what
little wits I have left became entirely scrambled.

So, if anyone is familiar with the Half Duo-Art and knows what
connection should be made to that nipple, I will be very glad to hear
from them.

Regards from John Phillips
Hobart, Tasmania