Quoted from HowardR:Hi Augie, welcome to pinside!
Order a schematic.
Tell us exactly which coil is buzzing.
Definitely agree on this ^^^^^^^^
I'm thinking QuietEarp may be on the right track though. You say score motor, but we might be having a bit of terminology confusion here.
The Score Motor is in the bottom of the cabinet and it revolves counterclockwise whenever scoring or game events are triggered from the playfield.
The Score Reels are in the back box and display the score. My guess is your score reel is not operating smoothly and needs to be taken apart and cleaned and lubed properly. follow the link below for some very good guidance on this.