One of the main problems is caused by the plug point. There are sparks at the plug point, due to which the plug is getting damaged due to corrosion, since it gradually gets eroded. The pins of the plug point will become black, and this affects the contact. So though the power is connected to the laptop, in reality due to the loose contact, there is no power supply. While the laptop can be used for some time, it will have to be recharged within a few hours
The blackened pins caused by oxidation of the metal due to sparking, heating can be removed using sandpaper. Yet when the abrasive is used on the metal, the oxidized layer is removed, affecting the dimensions of the pin. This affects the contact between the plug point and the pins of the cable.