Hoover Nextra HNC170 will not dry / heat up -suggestions?

My Hoover Nextra HNC170 Condenser tumble dryer is two years old and has suddenly stopped heating up and drying the clothes. It rotates, sounds normal, the fluff filter is clear, water tray empty, condenser clean and free from fluff. I have checked underneath, behind the machine etc and all vents inlet and outlet are free from clutter and fluff.
I have checked the user guide, trouble shooter etc and this does not appear to be covered in the lit. The machine is not tempermental and has not shown signs of any problem til now. Does anyone have any ideas or where I can get a blown up diagram of the internal workings of the machine as it is not covered under warrenty now.
Any help at all would be appreciated.
Many thanks