I hope someone here is able to help me.  I live in Denmark and a
colleague of mine has a music box that he in 2013 partly disassembled
in order to record the tones of the combs for a project making a
"digital instrument" (blatant vandalism!).

He the left the music box unfinished and of course he didn't take
any pictures of the process and left the parts lying around.  Having
removed the star wheel roller and the dampers he kept them in a small
plastic bag; this resulted in some damage to the dampers.  He did,
however, make a short movie of the music box playing a disc before he
did the disassembly.

We got to talking about it and I promised to try to help him make it
work again.  I am not an engineer, only an amateur with some mechanical
skill and a lot of patience.  ;)

Using the video and pictures on the 'Net I have succeeded in assembling
the whole comb/damper/starwheel-thing and it actually works.  The notes
sound, and the whole thing turns okay.  Two notes are broken (the
highest and next-lowest), but that was not his doing.  I have installed
the thing in the cabinet again.  As for now, I have decided not to
clean everything to "new"-shine, but rather leaving it as it was found.

Now for my questions/problems:

1) When a disc plays it makes a loud sort of "boing" sound at small
intervals, and the whole engine gives a jolt.  It seems to be the
disc that bends and unbends.  I'm told this was also the case before
the disassembly.  Could the problem be the alignment with the dog-wheel
that drives the disc?  Or something else?

2) The governor: what is the exact function of the this?  I understand
that it is driven by the endless screw, but what is the meaning of the
arm with the jewel?  (View picture Polyphon Governor.JPG)

3) The Start-Stop function?  When the spring is wound up the machine
starts and keeps going until the spring power is spent.  The machine is
not coin-operated.  I guess it works like this: it has a "button" that
starts the player (picture Polyphon Start-Stop button.JPG).  This hits
one end of the arm going across the machine and the arm lifts the
attached tab at the other end (picture Polyphon Start-Stop 2.JPG) from
the top of the spring-assembly and the machine starts turning.  When
the wheel has gone one round (one disc played) the tab is meant to fall
into a hole in a small disc that lies in a round slot on the spring-wheel
(picture Polyphon Start-Stop 1.JPG).

But this doesn't happen, and the wheel goes for another round.  What can
I do to remedy this problem?

Sincerely,
Henrik Ewald
Denmark

 [ 1. The tab that should lock the spring wheel?
 [ http://www.mmdigest.com/Attachments/15/11/04/151104_095733_Polyphon%20Start-Stop%201.JPG 

 [ 2. The disc where the tab should go?
 [ http://www.mmdigest.com/Attachments/15/11/04/151104_095733_Polyphon%20Start-Stop%202.JPG 

 [ 3. The start button
 [ http://www.mmdigest.com/Attachments/15/11/04/151104_095733_Polyphon%20Start-Stop%20button.JPG 

 [ 4. The governor assembly (in motion)
 [ http://www.mmdigest.com/Attachments/15/11/04/151104_095733_Polyphon%20Governor.JPG