Pull the carpet out and hang it on a fence then hit it with mean green and dawn. Scrub it down then rinse. You will be amazed at what comes off.... Just because the smell is "gone" doesn't mean the nasty crap that caused it is. Its still there.
Anytime I get something used, If I can, I spray it down with disinfectant spray, then mean green, then soak it down to wash. Including electronics. Some of the crap is nasty. As long as you let them dry, 99% of electronics survive water. Even computers. Just have to make sure all power is removed and is until subject is totally dry.