Thank you for your reply
flying the Triple Seven now for six years, still so many things to learn, but as a former airbus driver, I have to say that Boeing FCOMs dont provide a lot of background information

But I am very happy flying that beauty!
Plz correct me if I am wrong:
If the normal and alternate/reserve braking system is inop, I do have the pressure in the Brake Accumulator as final backup, and at the same time the Brake Source Light on captains side is coming up because the pressure for the normal and Alternate/reserve braking system is low, am I right?
Happy landings