Diagnosis
A large or rigid piece of debris is caught in the base station's impeller fan. Common culprits are cat litter granules, cereal, or pebbles.
How to Fix It
Unplug the base. Remove the clear debris canister. Shine a flashlight into the metal impeller chamber at the bottom of the base. Use long-nose pliers or tweezers to carefully remove any foreign object lodged between the impeller blades.
If That Didn't Work
The impeller itself may be cracked or damaged. Inspect the plastic blades for breaks. This requires part replacement.
Heads Up
Regularly check the robot's bin for large debris before docking to prevent this. The impeller is not user-serviceable; contact support if damaged.