Hi Eliyahu,  The problem with your unit is most likely the block
valves.  They need to be rebuilt.  The primary valves most likely
need to be rebuilt also.

One way to get the unit to play without crawling under the piano is to
shift the Play/Reroll lever very quickly from Play to Reroll and then
back to Play as soon as the holes in the trackerbar are all covered.

Musically,

John A. Tuttle