Definition
A printed circuit board (PCB) is the rigid board, usually fiberglass (FR-4), with etched copper traces that both physically mount electronic components and electrically connect them. Almost every modern device is built on one. An ASIC mining hashboard is a particularly demanding example: a dense, multilayer PCB that must carry very high current to dozens of chips while dissipating significant heat.
Why hashboard PCBs are hard
Hashboards use many copper layers and heavy copper pours to deliver the amperage each voltage domain demands. That same heavy copper makes them act as large heat sinks during repair, which is why a preheater and a hot air rework station are needed to reflow a chip without cold joints. The board's laminate can also be damaged by excessive or prolonged heat (delamination, lifted pads), so temperature discipline matters.
Repair implications
Faults can be in the components or in the board itself — a cracked trace, a lifted pad, a via failure, or moisture-driven corrosion. Tracing connectivity across a multilayer PCB usually requires a boardview or schematic, since most traces are buried in inner layers and invisible from the surface.
See the related repair entries on the solder wick, the schematic, and BGA packaging.
In Simple Terms
A printed circuit board (PCB) is the rigid board, usually fiberglass (FR-4), with etched copper traces that both physically mount electronic components and electrically connect…