Hi Tony,  First, as to the function of the various controls in front of
the keys:

The lever on the far left is 'manual sustain'.  It works like the right
pedal on any regular piano (the sustain pedal).  Typically labeled
"Loud", it was installed so that when the unit is being pumped with the
foot treadles, the sustain can still be used in the appropriate places
to enhance the quality of the music.  (Most Aeolian players also have
an 'automatic' sustain mechanism which operates the sustain pedal in
response to perforations on the music roll.)

The "switch" above the round 'on-off' button is most likely the
'on-off' switch for the automatic sustain mechanism.  Typically it will
be marked "On" "Off" and might have the word "LOUD" somewhere close by.

The two push-buttons next to the manual sustain are the Bass and Treble
Soft controls.  When activated, they operate a pneumatic device which
pulls the hammers closer to the strings in much the same way as the
left pedal on any regular piano (the soft pedal).

The main difference between the soft pedal and the push-button soft
controls is that the soft pedal pushes the entire hammer rail closer to
the strings.  The Bass and Treble soft control devices 'pull' a
secondary hammer rail which is split in the middle so the user can
reduce the volume of the music in either the Bass or Treble registers
independently.

The final lever (to the right of center) is the Tempo Control.  This
control allows the user to change the speed at which the music plays.
It usually has markings of "0" "70" and "110" or "120".  It is, in
effect, the speed gauge.  Although not usually very accurate (it's not
easily calibrated) except at the "0" and "70" marks, it should be
utilized to select the correct tempo indicated on the player piano roll
(near the beginning).

Inside the spool box, there is another lever (towards the right hand
side) which is marked "Play" "Re-Roll".  As those names imply, setting
the lever to "Play" allows the unit to play the music or "Re-Roll" or
rewind the roll.  Most Aeolian Sting players also have an automatic
Re-Roll mechanism which is triggered by special holes at the end of the
roll.  When triggered, it rerolls the roll automatically.  And at the
end of the rewind cycle, there is another device which senses that the
paper is no longer covering the brass tracker bar and shuts off the
electric vacuum pump.  This function only comes into play when the unit
is used electrically.  The auto 're-roll' function works whether the
unit is foot pumped or operated electrically.

Finally, there may also be another knob on the right hand side of the
spool box marked "Low" "Med" "Hi" or just 'Low' and 'Hi'.  This is a
three position volume control which works in conjunction with the
electric vacuum pump to control the general volume level of the unit.

Here again, as with the Tempo control lever, the amount of control is,
to a degree, unpredictable.  On some units, the degree of change is
fairly pronounced, from very loud to medium level.  On other units,
there is very little change from one extreme to the other.  Usually
this has more to do with the condition of the player mechanism in
general than it does the ability of the control valves to control the
level of vacuum created by the vacuum pump.

In closing, I would have paid at least $100 for the unit just for the
parts, and I don't buy or sell player pianos.

Musically,
John A. Tuttle (john@player-care.com)

P.S. This information will be turned into a web page which can be
seen at:  http://www.player-care.com/sting.html