Laser Unit And Toner Sensor Pcb - Brother MFC6800 Service Manual

4.1.13 Laser Unit and Toner Sensor PCB

(1) Disconnect the polygon motor flat cable, toner sensor harness, and laser diode harness from
the main PCB.
(2) Remove the three screws from the laser unit.
(3) Lift up the laser unit.
NOTE: When handling the laser unit, take care not to touch the inside of the unit, glass, or
mirror.
NOTE: On the small PCB at the right side of the laser unit is a 2-pin connector which is for
the adjustment in the factory. Do not disturb it.
n Reassembling Notes
• When replacing the laser unit with a new one, be sure to attach a ferrite core to the laser diode
harness of the new laser unit. Wind the harness around the ferrite core by two turns as shown
above, just like the laser diode harness of the old laser unit.
• On the underside of the laser unit, route the laser diode harness, polygon motor flat cable, and
toner sensor harness as illustrated in Subsection 4.1.25, "Harness routing G."
• Before putting the laser unit back into place, check for any toner particles, paper dust or dirt,
and clean them out.
• Make sure that the sponge is placed below the laser unit.
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