The USB hub on my desk died on Sunday. No lights, no enumeration, nothing. It is a cheap powered seven port thing I have had for years, so the sensible move was to drop it in the bin and order another. I opened it instead, because that is who I am.
The fault was obvious the moment the lid came off. One of the electrolytic capacitors near the barrel jack had a domed top and a faint crust of dried electrolyte around the vent. Classic. These low ESR caps bake themselves to death after a few years of sitting next to something warm, and a 470µF 16V part costs about ten pence.
Desoldering it was the fiddly bit. Old leaded joints behave; this board was lead free and the joints did not want to let go until I added a touch of leaded solder to lower the melting point, then wicked the lot out with braid. The new cap went in, correct polarity, stripe to the ground side, and I reflowed the two joints properly rather than leaving the cold blobs the factory had clearly been happy with.
It enumerated first try. Seven ports, all live, the little blue light back where it should be. Total cost: one capacitor and twenty minutes. There is a particular smugness to fixing a thing the world expects you to throw away, and I am not above enjoying it.