A USB-C charger may make a buzzing or whining sound because magnetic components such as transformers and inductors can vibrate during high-frequency switching. The sound can be more noticeable at no load or light load when the charger enters burst-mode operation. A faint, stable sound may be normal, while loud or sudden noise combined with overheating or charging interruptions should be investigated.

A USB-C charger may keep disconnecting because of a damaged cable, poor USB-C connector contact, failed PD negotiation, overcurrent protection, overheating, unstable output, device compatibility or excessive cable resistance. A charger factory should reproduce the problem, test different cables and devices, monitor PD negotiation, check thermal and electrical performance, and then identify the root cause before mass production.