someone kindly sent me a picture of the power supplies diagram/sticker. the connector has 9vdc output, 6vdc charge, a grounded shield, and a 5 v signal. what is the "5 v signal"? It's not labeled as an output, nor ac or dc. Is it a pin by which the p/s reads the voltage of the battery, so as to know when to stop charging? The specs state "Output 9V, 2 A max at supply, 6V, 1 A max at charging". ?Anyone have a spare that's surplus to their needs?