Reece's suggestions are sound: I can't tell you how many times, over the decades, I been called in to check out a failed boot drive only to find it was just a case of a loose connection or, perhaps, 'dirty contacts'; just remove the cable(s), give the connections on the drive a bit of a blast of air, hook'em up and see if that fixes it; you might also want to try swapping out the cable(s) for cable(s) known to be sound; cable failures rarely happen, but it would hurt to check...
<O>
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