Okay, Glen; The Dynavoice is not an easy piece to restore. Even
the most experienced player piano technician has trouble with this one.
The main problem is parts. I have successfully restored many of these,
even though I was told it was impossible.
In answer to a couple of your questions: The brown goo you speak of,
on the end of the tracker tubes, is a factory glue put there to seal
the joint, having aged over 40 years now.
Don't touch those joints. If the hose is cracked, just cut it off
an inch above the nipple, *leaving the hose and nipple alone,* and
merely seam another larger 1" section of hose, and then cut back down
to the smaller hose size.
As far as fixing all those broken nipples, it is caused by two factors:
age and a flaw in the original design -- the nipples are too thin and
weak. You can drill it out and fit it with a 1' long liner of copper
pipe and seal it all around with silicone caulk. This method will not
work, unless you are very careful with applying it.
You are better off with using replacement valve from a junker
Dynavoice. Find one and keep it for parts, or find someone who might
sell parts. Get ready to spend some money here.
I enjoy my Dynavoices and play them every day, all of them in optimum
playing condition. I also have gone far beyond the original factory
specs with these instruments, bringing them into the year 2000. One
of the typical problems is that they just play too fast.
Good luck, and prepare your self for long hours of restoration work
and high rewards.