Hi,
Not seen one of these for a while, but from memory!!! there is an exhaust filter built into the motor housing, remove the plastic that is over it and clean it well. If the cleaner has been used without the filter in the dirt bin then the motor fan will be full of hair and dust. it is possible to take the motor apart to clean it. The majority of these cleaners have had a new motor, as the originals burnt out within the guarantee. Apart from the motors burning out, we have not had any problems with them cutting out apart from what I have listed above. Non genuine replacement motors are available, but not really worth it.
Keith