he said he might use the BBBW power? so why are you trying to do all this other stuff?
Anyway, lets try to work through this all. Here’s the schematic. I have never seen one of these boards so I’m flying blind.
There are some unknowns - the Signal In section, not sure what it’s doing? IN1-IN6 don’t appear to be connected anywhere else. So lets ignore em.
5v is expected to supply the servos. That’s the reason for the 5v input options on this cape.
Option 1. You could simply jumper a wire from the 5v connection on the cape’s header pins, and connect that to the big 5v connector that supplies the servos. (this I’d expect is what the other fellow was suggesting)
Option 2. You could wire a separate 5v supply to the 5v in connector.
Option 3. You can figure out how to “split” the power from one power wall wart, to power both the BBB and the servos.
If you’re just going to use a couple of servos for playing around, I’d do option 1. If you want something more “robust” than a simple jumper wire, then you need to get creative. But since with option 1 or option 3 you’re powering it with the same wall wart, so you get no better current capacity to supply the servos, so it’s not really “better” in my view. So that’s why I say do nothing fancy with cables, just get a suitable power supply to run your servos, connected to the screw terminals and be done with it. So you’ve got two wall warts. No big deal?