(1) Adjusting Seeburg Roll Playing Tempo:  The small pulley on the
motor drives the large pulley on the rotary vacuum pump.  The large
pulley on the rotary vacuum pump turns a drive wheel on a shaft that
connects to the spool frame through a series of shafts and gears.

To slow the playing tempo, move this drive wheel closer to the center
of the big pulley on the rotary vacuum pump.

(2) How fast should the big pulley on the rotary vacuum pump turn?

The Seeburg rotary vacuum pump is a positive displacement pump.  Each
revolution removes a certain volume of air.  The faster the pump turns,
the more air is removed.  As long as the pump is rotating fast enough
to remove more air than required to operate the instrument, the music
will sound at the correct volume because it is regulated by the spill
valve and by the regulators in the Seeburg control box.

Therefore, if the nickelodeon is sounding too quiet or the music drops
out when the extra instruments play, there is not enough vacuum to keep
up with the demand.  Increasing the rotational speed (RPM) of the vacuum
pump will help.

If the nickelodeon sounds too loud, try adjusting the spill valve and
the regulators on the Seeburg control box.

Based on limited information I have collected, speeds for the Seeburg
rotary vacuum pumps are as low as 118 RPM and as high as 220 RPM.  Most
are between 160 and 210 revolutions per minute (rpm).

Wayne Finger