To repair faulty or damage trace pathways, you simply need to resolder or reball the board with the necessary material. This reconnects the broken circuit and allows electricity to flow freely throughout the board.
PCB is an acronym for printed circuit board. It is a board that has lines and pads that connect various points together. In the picture above, there are traces that electrically connect the various connectors and components to each other. A PCB allows signals and power to be routed between physical devices.
The most basic function of a PCB is to enable a simple action in an electric device. A PCB provides channels and pathways for the electricity and signals to follow. This allows a device to function on the most basic level. Without a PCB, a device might not even turn on.