Look for blockages in the air inlet holes on the shroud and the ball.
Dyson fan noise problem.
Dyson fans are notorious for getting clogged with dust at the bottom section and the turbine blades.
There s a problem with the oscillation.
The airflow should be strong enough to lift a sheet of newspaper past 45 degrees.
Try to clean the blower section of the fan.
Unplug your dyson personal purifying fan from the mains electricity supply before cleaning your machine.
Hold a newspaper approximately 2 meters 6 6 away from the product with the airflow control dial turned to maximum.
Brush the outside of your machine with a soft brush to remove any debris from the shroud.