EDN story from 2009. Excerpt.
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"The bad capacitor had a via at the positive terminal, but, at the negative end, there was a heavy trace going inside the footprint, beneath the capacitor, and only then outside. ... On the positive terminal, the solder stayed where it was supposed to, clinching the terminal to the PCB. On the negative side, however, during assembly, the melted solder drifted under the capacitor and solidified, lifting the negative end and bending the capacitor just enough to