Dear Major,  What you have described is a real treasure and you will
want to protect it as best you can.  I am not familiar enough with the
automatic changer mechanism that it sounds like you have; however,
I can offer the following advice:

1. Protect the Glass:

a. Remove the door and glass from the machine.
b. Tape across the surface.  If there is a decal make sure to tape
   only on the non-decal side.
c. Cover with cardboard
d. Protect in a wooden frame.

2. Let the spring wind down:

a. Play it as much as you can with out winding-then when it comes to
   the end of the last disc, let it play until it absolutely stops
   completely.  If you know how to "let down the spring", afterwards,
   do so.  If not, on a disc machine it's not as critical and letting
   it wind down is sufficient.

3. Secure moving parts:

a. The changer uses belts to raise the disc; disconnect them and
   secure the mechanism so it cannot move.
b. Secure the pressure arm to its location (should be okay on an
   automatic changer device).

4. Protect the musical combs:

a. Make sure that the star-wheels are in the rest position and are
   not in tension on a note.
b. Place strip magnets across the comb.  I would get enough to run
   two strips on each comb, so you'll need roughly 40 inches of magnet.
c. Tape the star-wheels so that they cannot move.
d. If you want to feel extra secure and understand how to place them,
   you can remove the combs and protect them in special cases.  Do this
   only if you are secure with this step.

Good luck with your move and in protecting your instrument.

Eli Shahar