Duo pb => please set disc

[Megahertz13]

Hello

I don't speak english very well , i hope you will understand my problem ^^

I have a japanese DUO which makes me the message "please set disc". By removing the console, I realize that the lens hangs on the left, the CD does not spin.
I replaced the lens with another I had in stock (from a previous DUO and that worked well). It is the same problem with additional one thing: the laser carriage motor keeps running as if he wanted to continue to cause the laser lens to the left. The RUN/SELECT reset stops the pb.

The hucards works perfectly.

I have no idea where the problem may come. Thank you for help me