First step is to remove the screws which keep the hp41 together, usually. The screws are located under the rubber feet, and under a grey foil, at least in my model.
After I opened the calculator it became immediately clear that the screw posts, which task it is to support the screws to put proper pressure onto the contacts of the key- and mainboard. Without proper posts the contact between different parts of the hp won't work correctly. A known problem.
As you can see on the picture the area around the upper screw holes at the lower cover were broken. In addition at the upper part the inner 2 of the "guidance" pins between the upper posts were broken not able to keep the in the right position.
Furthermore the right post of the lower ones was broken. Altogether a quite substantial damage even though my hp war treated gently in drawer.
According to a good repair instruction for this problem I began with the required steps to fix those problems.
This is described in Step 2 (still to be written as of now).
