To get the broken tip of the power connector out of the socket I did this trick successfully:
1. Cut a 1" piece of Gorilla tape or gaffer's tape.
2. Roll it into a cylinder approx the same diameter as the barrel plug, with the adhesive side of the tape facing out.
3. Insert the rolled up piece of tape into the socket, making sure the socket pin goes inside the roll of tape. Push it in as far as it will go.
4. Pull it out. The broken plug tip should be stuck to the tape. This might take a few tries.
It is inevitable that this fragile tiny plug will break in your FT-817 power socket. The tape will get it out.
I installed the N0WL Powerpole adapter on the FT-817 after this. Not a permanent mod, and it reliably converts the FT-817 to Powerpole, ruggedly attached to the ground screw.
Alexander N1PRW