Here is what I did. I attached a soft rubber hose to the AI, about 2 feet long. I rolled up the hose causing a pressure in the hose. I rolled until the AI read about 80, and then held it. The AI held the pressure for a long time. I then did the same thing to the D10. It would not hold any pressure at all. By connecting and reconnecting, I determined that my system is intact and without leaks, except at the D10. The installation instructions state that the port for the pitot is the center one.
I am beginning to get nervous that my D10 is defective, and even though I have not used it, it is out of warranty.