I had the same single port USB charger for a long time. I upgraded to a dual port charger, it lasted about 8 hours. Since I am traveling right now, I could not return it. So I decided to use my old one, it gets power, but didn't charge anything.
So I bought another one - in less than 8 minutes, this one as well failed.
I have checked for shorts and such, but nothing is acting up other than these chargers. I check with my cheapo travel DMM and voltages are what you would expect. I haven't blown any fuses either.
Anyone had problems like this? Did I just get a string of crappy units?
noteable mention both of my replacement chargers gave line noise - but only at low volumes, the noise actually disappeared - not drowned out by higher volumes.