PCB preservation.

We have some PCB�s in our warehouse in Manaus - Brazil. They are stored for more than 2 years , in a condition of 25 degrees centigrades and a humidity ranging from 60% to 90%. Do these conditions cause the PCB�s to deteriorate over time? If so , what kind of problems should I expect to have? Is there any advice to guarantee solderability ?

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| We have some PCB�s in our warehouse in Manaus - Brazil. They are stored for more than 2 years , in a condition of 25 degrees centigrades and a humidity ranging from 60% to 90%. | Do these conditions cause the PCB�s to deteriorate over time? If so , what kind of problems should I expect to have? | Is there any advice to guarantee solderability ? | | You've sited some of the most sever PCB storage conditions imagineable. Yes, no matter the plating or coating, these conditions will cause deterioration. However, the best solder surfaces are those tin/lead plated/fused and gold plated.

If your boards are OSP, HASL'd, or other, chances are not good for solderability guarantees notwithstanding other deleterious effects as moisture absorbtion in the substrate material.

Other issues affecting solderability may relate to atmospheric conditions as acid content and the type packaging material/methods used for preservation. If excellent care was taken in packaging and storage as air tight, dessicated containers, you might have a shot.

One way to find out is to solder some of the boards. You never know. That's why there are no guarantees but effective process management from design through fabrication, assembly, test, and acceptance.

Earl Moon

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