PS2 slim spch 90004 disc won't spin

my PS2 slim 9000 series is moded ,when i dissamble the PS2 to change lens (the old lens is working fine) i added a new lens for it but when i started the PS2 by holding the sensor lid it won't move…please help me only one sensor lid is available for a new model 9000x series i there any other switch i have missed…