According to the schematic on ipdb, the large bell coil is found at reference point G-21.
https://www.ipdb.org/files/961/Williams_1966_Full_House_Schematic_submitted_by_Steve_Corley.pdf
If you trace downward, you can see the bell coil is supposed to be fired by switches in both the 10-point and 100-point relays.
You mentioned chimes. Perhaps some prior owner retrofitted chimes into your machine?