HP 3150 EN - Manual (Page 101)

EN Document scanner assemblies 99
4 To release the right hinge of the document release door from the
printer door, use one hand to simultaneously press the right side
of the document release door toward the left and pull the printer
door frame to the right.
Figure 27. Document release door removal (2 of 2)
5 Lift out the right side of the document release door, and then slide
it to the right to release the left hinge.