Dyson rollerball vacuum - broken (Stretford M32)

I have a Dyson rollerball vacuum which does not work properly. Motor is fine but it will not pick up. I have viewed various You Tube videos and taken it apart etc etc but cannot get it to work. Might be something simple but it is beyond me. If anybody wants to pick it up and have a go at fixing it they are welcome. Located in Stretford M32