I have a few Terastations. One is a TS5400DE4A. But, it only has two drive bays. I was under the impression that the TS5400 series had four drive bays. I can't find any information on that specific model number. Perhaps someone swapped out the guts of a TS5400 and put them into a TS5200 case?? It works fine with two drives, and says drives 3 and 4 failed. Any thoughts?