This sound effect can be found on The Premiere Edition Volume 1, which was made by The Hollywood Edge. It is a recording of a Simplex Time Recorder 4090-2 6" 120 VAC bell ringing continuously and loudly. A similar sound effect, a low pitched version that is BELL, SCHOOL - SCHOOL BELL: INT: LONG RING can be found on the Series 6000 Extension I Sound Effects Library (produced by Sound Ideas). Links: https://soundeffects.fandom.com/wiki/Hollywoodedge,_School_Bell_Long_Ring_PE193201#Audio_Samples