rui_v wrote:
I did that. No batteries overnight. No result.

I also inspected the radio trying to find a reset button...nothing.
Maybe it's inside it, but I wouldn't like to open because of the
warranty (and also because I am not sure there is a reset button
inside).

So, still lost

But thanking for your trying to help. I do need ideas...

Even though your batteries are presumably new, did you test them
(preferably with a tester that puts them under load)? There is a small
chance one of the cells is defective. A long shot, but after testing
them, you will have at least eliminated a possibility.