The hardest faults to seek out are people who come about only once in a while—intermittent events. They may be a result of lousy connections, dust, dirt, corrosion or just damaged wiring or connectors.  trong m?t kho?n th?i gian nh?t ??nh tr??c khi ?i?u ch?nh, t?t nh?t b?n nên d&