Hard Drive failed on computer. Since it was seven years old, bought new iMac and decided to repair this old.
The repair essentially went as advertised except for item listed below.
Had to do in stages as instructions stated need same manufacturer for hard drive so that temperature monitor connection would be appropriate. Even after doing this still had issue. Connector from computer had tab on one side that defined orientation, but socket on new disk did not have slot for this tab. I cleaved the tab off with a razor blade so that connection could be made.