Talked to Antec. Total failure of ecommmerce. Their site does not mention the part which I so desparately need. SL300XR. You can only get it if you call their 800 number. Which was answered by a human on the second ring, who was able to tell me how to obtain the part. (Only by calling.)
They do tell me very clearly on the web site how to test it, this is how I knew it need to be replaced. I guess if the manufacturer tells you to put power supply outputs, it's OK, no matter what Mom said when we were kids.