This console has unused sounds.
The Konami Bubble System is a CPU board that uses special bubble memory cartridges to store game data. Unfortunately, said cartridges were extremely susceptible to corruption from magnetic interference, and combined with the high cost of bubble memory at the time, Konami ended up producing only five games for the system, all of which were eventually ported to more conventional arcade hardware.
An unused "60" sample. The initial boot-up starts at 50 seconds, not 60, so this isn't needed.