Hi, i'll try to write in english..

some times i've heard about this problem, i know on cdrom readers there is
a lever type switch with the lever pushed in one side when tray opens and the
other when it closes, if when the user commands to open, the tray reaches
the end of the run the board (i think) senses motor's too much current use and
revert the direction, i think the switch is a single contact but in some way
when the tray closes there is no invertion or maybe the switch has 3 contacts
but 2 are common so the "close" contact works, the "open" not..
this sw. is on one side of the tray, if you watch under the bottom side is made
like __/'''''''''''''''''''''''''''\___ this... it is on the front, i think.
i've been clear?

Bye..