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92 SMT007 MAGAZINE I MARCH 2021 Electronic components and their availability (or rather their lack of ) have been in the news recently. Automotive suppliers are struggling with their supply chain as electric vehicle pro- duction, and the associated consumption of electronic components, continues to expand. Fabless semiconductor companies lacking capacity have also been in the news with their deliveries pushed out to 2022. All this news, and the ever-shortening life cycle of semicon- ductor devices, have le some electronic man- ufacturers wanting for supply. In some cases, shortages of given components can be met by harvesting them from existing assemblies. e harvesting (Figure 1) of electronic com- ponents from circuit boards allows obsolete, expensive, long-lead-time order electronic components to be re-used. ese components can be harvested from scrap piles, from obso- lete assemblies, or by other means. Care must be taken to ensure that the components can be reused in a manufacturing environment, and given the greatest chance for a reliable compo- nent to be soldered in place. Disassemble the Hardware e first step in salvaging components from an assembly where valuable electronic compo- nents are soldered in place is the dissembling of the hardware. is operation may include the backing out of screws, and the detachment of sub-assemblies and larger components, such as heat sinks, fans, and power supplies. Begin the Salvage Operation Once all the mechanical sub-assemblies have been taken off the board, the salvaging oper- ation can begin. It is critical to understand all the requirements from the end user, includ- ing items like the packaging of salvaged com- ponents, removal or non-removal of conformal coatings, the MSL level of the components, and many other aspects. MSL Level If the PCBs have been held in open storage or are field returns, the mois- ture sensitivity level, (MSL) of the to-be-removed components gener- ally requires a pre-bake of the com- ponents prior to removal. is will help ensure the long-term reliability of the component to be salvaged. Knocking Down the Bone Pile by Bob Wettermann, BEST INC. Salvaging Components for Other Uses Figure 1: Should used printed circuit boards be considered scrap or salvage?

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