Brother MFC Series Service Manual page 163

Document scanning position sensor PCB ASSY
(14) Turn the ADF unit downside up.
(15) Push the lock arm towards you, remove the front end of the Document scanning
position sensor PCB ASSY from the lock arm, and take out the Document scanning
position sensor PCB ASSY. Disconnect the Document scanning position sensor
harness from the PCB.
Document scanning position
sensor PCB ASSY
ADF harness ASSY
Document scanning position
sensor harness (red)
(Rear)
ADF unit
Lock arm
3-55
(3_072)
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