Robot mower is very noisy during operation; grinding or rattling sounds from underneath.

Safety first: Turn OFF the mower, remove it from the lawn, and wear gloves before inspecting the underside.

• Inspect blades and disc: Check that all blades are present, not bent, and that their screws are tight. Replace any damaged blades.
• Remove debris: Clear any stones, twigs, or compacted grass from around the cutting disc and motor area.
• Check disc bearing: Rotate the disc by hand and listen for grinding. Any roughness suggests a worn bearing or motor that should be replaced.
• Listen to drive motors: With the mower upside down (and OFF), spin the wheels by hand. Excessive noise or roughness may indicate a failing drive motor assembly.