When you inserted a dollar, the acceptor sent a voltage pulse (a "credit pulse") to the logic board. The logic board incremented the credit counter. You then typed A-1-2; the board deducted one credit and queued the song.
Push the service switch back in or close the door. If successful, the display should show "99" or "Free," indicating unlimited credits. For NSM Digital Wallboxes Nsm Music Jukebox Hack
The latter approach results in a rock-solid jukebox with terabytes of music, Spotify/Tidal integration, and a modern search interface—all while the external world sees a beautiful, original NSM “Performer” or “Galaxy” tower. When you inserted a dollar, the acceptor sent