We've (mostly me) have been discussing USB power banks in Shinyitus, but I thought it is more general in nature.
The image above is the USB 2.0 port. There are two, labeled for a 1Amp output and one labelled for 2.1A output. (I don't know why they went for the 0.1). Either one will work for this.
Turn the power bank on. (Duh!)
With your voltage tester, put the black probe on ground, and the red probe on power. I had to use a lighted magnifier to do it and it took a lot of tries. But when the needle on your tester jumps, it's all worth it.
The image above is the USB 2.0 port. There are two, labeled for a 1Amp output and one labelled for 2.1A output. (I don't know why they went for the 0.1). Either one will work for this.
Turn the power bank on. (Duh!)
With your voltage tester, put the black probe on ground, and the red probe on power. I had to use a lighted magnifier to do it and it took a lot of tries. But when the needle on your tester jumps, it's all worth it.