The hardest faults to discover are the ones that transpire only once in a while—intermittent events. They are often attributable to bad connections, dust, Dust, corrosion or just broken wiring or connectors.H?c ??n l?p 9, ng??i cha ??t ng?t qua ??i, gánh n?ng kinh t? ?? d?n vào m? nên V??ng ngh? h?c s?m, nh??ng c? h?i cho các em. Gi? x? s? m