If you had it serviced about 10 years ago, what exactly was serviced?
These appliances have electric motors in them, and they used carbon brushes.[br]
Those brushes are considered wear-parts, and needs to be replaced in intervals, depending on frequency of use.[br]
Along with replacing the brushes, it's good practice to clean all contact points as the wearing of the brushes collect and needs to be cleaned to provide good contact.
One important symptom of bad / worn brushes, is the loss of power in the appliance, which is what you describe.