HP-41C - serial 2052A - Memory Lost

[Vintage63]

Peter, you are correct!! I tried prying open the shell at the back and on one side it separates by over 1 mm.
Tried switching it on after doing this and it wouldn't start. Fortunately when it did after a few secs it lit up and worked flawlessly.
I also added new rubber feet that I had lying in the tool case, it now looks a bit like a monster truck as these are a quite thick :-)
I'll search on the forum how to make the two shells stick together properly.
I could start by tightening the screws with a light turn but would not want to brake what is holding on to dear life at the moment :-)
Thank you
Marco