Looks as though more folks have been putting "bargain" power supplies to the test and finding them wanting. This time it is a 5 volt USB power supply purchased in the UK that fails to deliver its advertised load.
"I am often asked how radio works. Well, you see, wire telegraphy is like a very long cat. You yank his tail in New York and he meows in Los Angeles. Do you understand this? Now, radio is exactly the same, except that there is no cat." : Albert Einstein