Check you batteries
Did some reloading two nights ago on my 650 with the primer buzzer and powder check buzzer and everything was working fine. I always know within a few rounds when the primer buzzer is gonna go off. Last night however as I was getting ready for it, it never went off. I reach up hit the switch and nothing. Pulled it off and checked the battery, corroded top and bottom. I would be willing to bet that the original batteries were in both units(9-10 years). A little scraping on the contacts and I was back in business. The battery in the powder check was fine, but it went in the trash as well.