Burgate Opti Mist... no mist?

Hi.
Burgate optimist isn't producing the mist effect. Have replaced the transducer (£48)…. but still no mist. So it points to the Sump Fan. checked and that isn't spinning. SO..... how easy is this to do myself ? I have heard the callout fee for one of the Dimplex techs is huge for what it is. If its a case of taking it apart, mounting and pluging in a new unit.... then I am more than capable of htat. Just wondered how much of a job it is. cheers