I have a pile of power supplies which used to power CCTV cameras. They're rated at 12V 1A. They're very light and give out precisely 12V with no load, so they must be regulated switched mode. So why is it when I try to power a 0.15A 12V fan (a 120mm Corsair computer fan), they fail very quickly? The first one started whining and gave out only 0.5 volts after only half an hour, and the second one went pop after half an hour. I've had two of the others powering door entry RFID coils and the door solenoids and they've been happy for a few years.

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Why are hemorrhoids called "hemorrhoids" instead of "asteroids"?