When you get $thing from China and it comes with a "5V 2A" PSU that weighs 40 grams, has a single diode rectifier at the input, logic consisting of two transistors, no Y cap, no feedback, and a transformer with a single layer of tape and enamel separating you and AC mains.
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Did you measure its actual output? I've seen EEVBlog measure some and they were abysmal
It was 5.5V no load and I was too lazy to do a proper test, but I doubt it could handle 500mA.
