Brother support
Replacing the drum unit
DR350 - DR360 - DR420
Instructions (PDF)
Brother DR350 - DR360 - DR420; replacement and reset procedure.
DR520 - DR620
Instructions (PDF)
Brother DR520 - DR620; replacement and reset procedure.
DR630
Instructions (PDF)
Brother DR630; replacement and reset procedure.
DR720
Instructions (PDF)
Brother DR720; replacement and reset procedure.
DR730
https://www.youtube.com/watch?v=h7dJpvf_Hyo