General Player Tubing

Below, you will see a couple of hand drawn pictures of the insides of a Lauter-Humana Player Piano. Most player pianos are tubed basically the same way. By identifying each of the major components of the system and testing each one separately, you can locate major problems very quickly. The average player mechanism is comprised of six major components. They are: the stack (which contains all the note bellows [strikers] and their associated valve), the lower section (which generates and stores the vacuum), the air-motor (which makes the roll go around), the air-motor governor (which controls the speed of the motor), the tracker service (which keeps the roll aligned with the holes in the tracker bar) and the transmission (which makes it possible to shift from Play to ReRoll)

All of the other devices in a specific unit are more than likely used to modify or enhance the sound of the music being played. The most common peripheral devices are the Bass Soft and Treble Soft, which lower the volume of the music in the Bass and Treble respectively and the Auto-Sustain which performs the same function as the Sustain pedal on the piano. As indicated in the drawing, the Auto-Sustain usually has an associated switch in the spoolbox that enables the user to turn that function "ON" and "OFF".