If a regulator-rectifier is thought to be defective, it should be:

Testing and replacing a regulator-rectifier is the appropriate course of action when it is suspected to be defective because these components are critical for regulating voltage and converting AC to DC power in outdoor power equipment. When a regulator-rectifier fails, it can lead to significant issues, such as improper charging of the battery or failure to provide adequate power to the equipment.

Testing the unit allows you to confirm whether it is indeed malfunctioning. If it is found to be defective, replacement is often more efficient and reliable than trying to repair or rebuild it. Regulator-rectifiers are typically designed to function as complete units and may not have replaceable parts. Additionally, precision in voltage regulation is crucial for the functioning of modern outdoor power equipment, and replacing a defective unit ensures reliability and performance.