Soldering to a PC board can be tricky: Too much heat can make the copper trace lift right off the board substrate. Use a soldering pencil rated at 15-25 watts, no more. (Watch the video; story ...
Good Lord, is there anything you can’t plug into a USB port? Now it’s the turn of the soldering iron, something you’d think likely to need a lot more than the paltry five volts a USB bus can offer.