Hi there. We regret to learn that you're having a rattling noise and not heating issue with your LG smart inverter. Please check these links for good-to-know information and troubleshooting to solve the issue with your unit: www.lg.com/us/support/help-library/lg-microwave-why-is-my-microwave-not-heating--1428511871544 and www.lg.com/us/support/help-library/lg-microwave-troubleshooting-noises--20152329269153. If the issue still persists, please send us a private message on social media using @LGUSSupport with your contact information. We're here to help. ^Win