Forum:Safehouse claptrap 2nd PT

Claptrap Safehouse SDU 2nd PT

I've been trying to get a 2nd sdu from the claptrap in the safehouse. Is it possible to get one from here? I've heard you can get extras from the first 5 missions but on the mission article it says you can't. People have also said they've been able to get it after 3-4 tries but I've tried so many times and it hasn't given it to me. Is there anything to increase the chances? Does it stop at a certain point?