Replacing the carbon brushes on a Dyson vacuum cleaner motor is very cost effective so it’s usually worth trying before replacing the motor.
Checkout the video and procedure below to see how it is done.
This is how to repair a Black & Decker steam mop that is not producing any steam. The symptoms are that the steam mop is hot and makes a buzzing noise but no steam is produced. The fault is due to a small one way water valve in the body of the mop becoming stuck closed. The video show you how to dismantle the steam mop, remove the valve, repair the valve and then reassemble the steam mop.