Canon SmartBase PC1270D scanner lamp problem

About the printer canon SmartBase PC1270D. The problem is, when I start to make a copy using scanner, the scanner lamp is moving to the right end and stay there, in this time the engine for moving the lamp to the end is trying, forcing to move more and more, but it is no more space to move. It seems like the engine which action to the lamp move hase no information from any of sensor that the lamp is at the end. This is all, with 2 more tries the engine jumps each time one stap in forcing onto the belt jagged used for sliding scanner lamp. What the sensor for the right end? I see no one, maybe is the lamp? How can I cech the lamp or the sensor?

thank you for any help,
antonio1