Background: We had a PWA fail in the field after approximately 6-7 months. The unit was powered on approximately 1000-2000 hours. Analysis of the PWA revealed a short had developed between two parallel traces underneath an IC. The traces are .006" wide and .010" apart. The short was not visible (even under a microscope). The short was approximately 2 1/2 ohms in value. Once a razor was run between the traces the short was eliminated and the PWA was functional once again. Someone I spoke to at a PWB Fabricator suggested it might have been dendritic growth. Questions: What is dendritic growth? Does causes it on a PWA? Where can I get more information about it? Can it be attributed to the PWB fabrication? Any and all assistance is GREATLY APPRECIATED! Best Regards, Mark Lettang 3M [log in to unmask] (507)359-0418