Ricoh SP C400DN User Manual page 53

I
Fasten the four screws to attach the cover.
J
Align the controller board with the left and right rails, and then push it
carefully in, until it stops.
Push on the area of the controller board that is marked "PUSH". Push in the
controller board until it can go no further.
The printer may malfunction if the controller board is not properly installed.
K
Fasten the controller board to the printer using the three screws.
Attaching User Account Enhance Unit Type E
AQC700S
AQC710S
AQC720S
2
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