There is a guy at HP (from Compact from DEC) that works Friday Evenings and week-ends that may be able to help.
His name is Robert J. Schmalstieg. Real sharp guy. New VMS internals and Data Structures of the top of his head. If you can get in contact with him, he may be able to tell you what needs done.
After re-booting the VAX its still can't see the drive huh?
Have you looked at the errorlog? It was something like,
"Ana/err/since=" I forget the time syntax.
Have you tried all of the ports on the KDA-50?
If you get errors in the errorlog you could post a copy and I may be able to interpret.
Ben
PS See my bio to see why I understand anything you have said.