There are a lot of things that can go bad inside. Follow instructions in your book to clean and recalibrate. Do not open the top cover / sensor & electronics housing, nothing to see inside really. Check the mesh membrane for damage and replace if needed, not expensive. Check valve actuator at the back of unit, this regulates the ipa supply. If the alcosmart is damaged it's too expensive to repair. Best to look for a second hand tested replacement, AZR ideally.