Thrift Store Roomba

I found an original model Roomba robotic vacuum cleaner at a local thrift store for $6. It was full of dust and hair and missing the AC adapter, but I figured for $6, it was worth a shot. I noticed that the Roomba has a weird power connector consisting of two inputs. iRobot has their Roomba manuals available as free PDF downloads and the manual shows the special adapter that originally came with the Roomba. They sell replacement AC adapters but they don't come with the double-barrel adapter. I posted to the official Roomba forum, and the best suggestion I got is to look for someone selling one with a broken Roomba on eBay. Given that I don't know if this Roomba even works, I'm not sure if I want to spend much money for a replacement AC adapter. Since I do have some basic electronics and soldering skills, perhaps I can build an adapter myself? Even if I do get the Roomba working, the programming options unfortunately aren't available for original Roomba models. That's no big deal. With the way that cat hair and dust form little tumbleweeds on my (fake) hard woods floors, an automated vacuum would be great. At worst, I can always sell the Roomba on eBay for spare parts.