Thanks to all for support!!
I have also a C65 keyboard to control the board and i saw the preliminary manual for C65 (the archive that i didn't know is very useful i think). C65 in my opinion should have been a game console with possibility to turn in a computer with add-on. Great graphic system, powerful, fast and easy to program should have been useful for gaming. And i agree with Fishy_fiz when he says that many users were faithful to C64 and didn't want change with Amiga..
Take care, have a nice day
Ciao
Carlo