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The damage to the board was caused by a tool like a pair of tinsnips, crushing the layers of the board together while cutting. The tiny layers of copper are fol
by RodgerTheGreat 2y ago
The damage to the board was caused by a tool like a pair of tinsnips, crushing the layers of the board together while cutting. The tiny layers of copper are folded together at the edge of the cut, causing shorts. By sanding away the board at a much shallower angle than the original cut it is possible to expose an edge along which no conductive layers are bridged.
As for how the board still works when that area is cut out, probably just a degree of luck that none of the traces that were severed were essential?
- Wowfunhappy 2y agoAh, thank you! So it wasn't actually the cut that "broke" it, it was the fact it was crushed.
- simondotau 2y agoBased on appearances, the board has a tight cluster of components laid out similarly to a contemporaneous iPad. The rest of it seems like a vast empty wasteland, lightly populated with debug terminals, ports, and compatibility shims which make it work inside a Mac mini chassis. Chances are the breakage caused a power rail to short and the “repair” fixed the short while leaving one or two debug points inoperable.