I know what you mean about coincidences: in my case the day before I had wired in a new (powered) DAB aerial and despite knowing deep down that simply laying RF cables in front-to-back, and a new 12V feed in the rear, couldn't have caused the smoke, it didn't stop that nagging doubt about what I might have got wrong.

It was exacerbated because I couldn't see the source of the smoke, so couldn't be sure I'd pin pointed the source until I pulled and checked the fuses one-by-one.