In MMD 10.07.25 John Philips wrote:

> ... 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.

Hello John,  My Steck half-Duo-Art has the slider switch for the Duo-Art
On-Off control.  There are four tubes connected underneath, and the rear
one is a smaller diameter than the first three.  Unfortunately I can't
tell you where it goes without removing the top action.  I should have
a sketch somewhere, but I haven't seen it in 20 years.

Let me know if you don't get an authoritative answer I'll pull the
action out and have a look, but there's no guarantee that there were
ever two of them the same.

Best regards,
John Wolff
Melbourne, Australia
http://www.vicnet.net.au/~wolff