I'm modifying an old 1960s darkroom timer for use as a kitchen timer. It works fine but the buzzer could wake the dead, plus once it goes off the user must manually switch it off. So I'd like to either modify it so it sounds only briefly or replace it with something else. I'd prefer to keep the modifications analog. I've attached a photo. The red circle on the left is the on/off switch. The other is the buzzer. It runs on US household current.