Welcome Robertino.
Don't worry too much about your English, if you promise me the Italian won't laugh too hard in my face when I try and speak Italian when I'm over next summer. ;-)
Now to your question. Don't worry too much about the screen being off-center. It's not your Amiga at fault. Your TV-sets should be okay too.
While in workbench, you can try and resolve the problem by playing about with the overscan settings (Sys:/prefs/overscan). It gives the possibility to move the screen around a bit and it also allows you to stretch it a bit to make it fit your tv. Unfortunately, this won't work with the games that don't run from the Workbench. If the picture is off just a few pixels then don't worry about it, while playing games it shouldn't be a big problem.
Well, that's my few cents. If someone has a fix for the non-workbench games I'd love to read it ;-)
Oh... you have already checked for adjustments on the tv?
