My Maytag three year old dehumidifier mak...

My Maytag three-year old dehumidifier makes a throbbing/pulsating noise when running and no longer removes moisture from the air. I cleaned the unit thoroughly, including the filter, but there is no improvement in performance and the throbbing/pulsating noise continues. Is this unit expended? Any ideas before I purchase a new unit? I would have thought that the unit would have given me more than three-years service. Thanks in advance for advising re this problem.