If your Dyson vacuum doesn't pick up items from the floor as effectively as it should, the filter may need to be cleaned. This is especially true if you have owned your vacuum for a long time and never cleaned the filter, or if you have used your vacuum several times since the last time you cleaned the filter. You should clean the filter at least once every six months to prevent the filter from clogging.
The brushbar is located inside the mini turbine head and is controlled by air flow. If your vacuum has a blockage, the brushbar may not spin properly because the vacuum is not getting the appropriate amount of air. The air flow may be blocked by small items that the vacuum has picked up from the carpet or by a build up of residue. The brushbar may not turn properly because a thread or other fabric is wrapped around it.
If your Dyson vacuum is overheating, it will turn off and on intermittently or it may not turn on at all. If the machine gets too hot or it's emitting a foul smell, you need to discontinue use and let the vacuum cool off. More than likely if your vacuum is overheating, it's because the machine is not getting sufficient air through the mini turbine.
If your Dyson vacuum does not work properly or it fails to start, you need to double-check the assembly instructions and make sure that you have assembled the unit correctly. Installing any of the parts of your Dyson incorrectly can result in the failure of your machine to work properly. Follow all instructions included with your unit.