Brother International MFC 8500 Service Manual - Page 157

If the horizontal stripes appear at 39-mm intervals, replace, the toner cartridge.

Page 157 highlights

Trouble (5) Black and blurred vertical stripes or band (6) Black vertical streaks on gray background Action to be taken At the scanner Check the following components: - CIS unit At the printer side l Clean the paper path which may be contaminated with toner. l Slide the wire cleaner to clean the corona wire inside the drum unit. l Make sure that the wire cleaner is returned to its home position. l Replace the toner cartridge. l Replace the drum unit. l Replace the heat-fixing unit. At the printer side l Clean the laser beam window (glass) on the laser unit. l Replace the laser unit. (7) Black and blurred horizontal stripes (8) Horizontal lines At the printer side l Slide the wire cleaner to clean the corona wire inside the drum unit. l If the horizontal stripes appear at 39-mm intervals, replace the toner cartridge. l If they appear at 94-mm intervals, replace the drum unit. l If they appear at 79-mm intervals, replace the heat-fixing unit. l Clean the grounding contacts. (Contacts Q in the illustration given on page VI-28.) l Replace the high-voltage power supply PCB. At the printer side l Check the connection between the right end of the paper feed roller and the grounding wire. (Contact W in the illustration given on page VI-29.) VI - 23

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VI
- 23
Trouble
Action to be taken
(5)
Black and blurred vertical
stripes or band
At the scanner
Check the following components:
-
CIS unit
At the printer side
l
Clean the paper path which may be contaminated with toner.
l
Slide the wire cleaner to clean the corona wire inside the
drum unit.
l
Make sure that the wire cleaner is returned to its home
position.
l
Replace the toner cartridge.
l
Replace the drum unit.
l
Replace the heat-fixing unit.
(6)
Black vertical streaks on
gray background
At the printer side
l
Clean the laser beam window (glass) on the laser unit.
l
Replace the laser unit.
(7)
Black and blurred
horizontal stripes
At the printer side
l
Slide the wire cleaner to clean the corona wire inside the
drum unit.
l
If the horizontal stripes appear at 39-mm intervals, replace
the toner cartridge.
l
If they appear at 94-mm intervals, replace the drum unit.
l
If they appear at 79-mm intervals, replace the heat-fixing unit.
l
Clean the grounding contacts. (Contacts
Q
in the illustration
given on page
VI
-28.)
l
Replace the high-voltage power supply PCB.
(8)
Horizontal lines
At the printer side
l
Check the connection between the right end of the paper
feed roller and the grounding wire. (Contact
W
in the
illustration given on page
VI
-29.)