Dell 2130cn accessing internal components

Hi all,

I have a Dell 2130cn that is coming up with a paper jam error, yet there is no paper in it. It looks like the first white plastic paper sensor above the paper tray (at the bottom of the unit) has lost its spring, and hence is "telling" the printer that there is paper stuck in the input. I have removed the sides of the printer and pulled out the main print head (?) unit from the front but can't access the platic white sensor. The closest I can get is taking the main paper roller out underneath. Does anyone have a service manual or information on how to access this part so I can see what is going wrong with this unit please? 

Thanks

JD