Hacking Brother MFC-7420 Toner Catridge - simple, but effective
I still receive the error message "Replace Drum", "Drum End Soon", "Drum Near End", or "Drum Stop" after I replace the drum unit with a new one. | Brother
Remove Drum and Toner | Brother MFC7240 - YouTube
Brother MFC-7420 Toner Cartridge and Drum
Brother MFC-7420N or MFC-7820N How to reset toner warning “Toner Life End”