Posted for "colyncase on earthlink" <colyncase@earthlink.net>:

 As noted in a previous post, my stec55x installation had similar problems.
 After messing with pretty much all the components over a period of a year
 it really did all come down to the connector on the tray.   It's not a great
 connector in the first place but the housing is made of plastic so that the
 mounting bolts get loose in the housing.
 
 I replaced all the pins, the connector and the housing and the problem went
 away.   ....I don't remove the computer very often these days.....
 
 Colyn Case