Brother HL-820 Service Manual page 58

Note:
When replacing the scanner unit, ensure to assemble the ferrite core using the cable
binder as follows;
Cable binder
(3) Disconnect the three connectors from the panel sensor PCB.
(4) Remove the M3x8 tapping screw, and lift the toner sensor PCB from the scanner
unit.
Caution:
Never touch the inside of the scanner unit or the mirror when disassembling or
reassembling. If there is any dirt or dust on the mirror, blow it off.
Toner Sensor PCB
LD harness
Fig. 3-13
Fig. 3-14
III-9
Ferrite Core
Flat cable
Taptite, cup M3x8
Scanner Unit