The soldering iron's tip was too fat, making me put solder all over the adapter. I don't have soldering iron with skinny tip. I ruined the adapter trying to solder the 0.1" headers to the adapter. The 2mm headers were already soldered on the adapter at the factory. I need 5V/3.3V adapter with all headers already soldered to the adapter at the factory. If the 2mm headers aren't soldered to the adapter at the factory, I would solder the 0.1" headers to the adapter before soldering the 2mm headers to the adapter. The yellow LED doesn't light when I connect 5V and GND wires to the adapter.