Brother Facsimile Equipment MFC7420 - Manual (Page 230)

Confidential 9-42
I-17 Black band
Possible cause Step Check Result Remedy
Ground
contacts
Corona failure 1 Is the wire cleaner at its
home position? No Return the wire cleaner
to its home position.
(2)
Corona dirty 2 Is the corona wire dirty? Yes 1) Clean the corona
wire.
2) If the problem still
appears after
cleaning, replace the
drum unit.
(2)