Canon Perfect Binder A1 Troubleshooting Manual page 264

A warning message may be displayed and stay on even if the
waste paper box is housed. Caused by the detection sensor
bracket deformed.(PerfectBinder-B1/PerfectBinder-D1/
PerfectBinder-E1)
[Symptom]
A warning message "The trim waste unit of the Perfect Binder is pulled out." may be displayed and stay on even if the waste
paper box is housed.
[Cause]
If the waste paper box is housed roughly, the bracket [1] that fixes the sensor to detect open/close state of the waste paper box
gets deformed. Because of this, the waste paper box open/close detection sensor flag [2] stops to operate normally, and this
leads to the aforementioned symptom.
[Service work]
If the symptom occurs, prepare the new type detection sensor bracket(FE4-9766-000). By following the procedure below, replace
the detection sensor bracket with this new type. Note that the following description starts from the step in which Perfect Binder
is disconnected from the Main Body of MFP.
1) Remove the front cover (Right/Left)
1-1) Open the front cover (Right/Left).
1-2) While holding the front cover (Left), remove the upper/lower hinges to remove the front cover (Left). Pull the hinge in the
direction of arrow while pushing the black lever to remove the hinge.
1-3) Remove the front cover (Right) in the same manner.
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