Path: utzoo!attcan!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!rutgers!ucla-cs!admin.cognet.ucla.edu!casey
From: casey@admin.cognet.ucla.edu (Casey Leedom)
Newsgroups: comp.sys.apollo
Subject: Re:  Can you swap drive electronics packages?
Message-ID: <16777@shemp.CS.UCLA.EDU>
Date: 13 Oct 88 19:22:16 GMT
References: <8810131422.AA04631@richter.mit.edu>
Sender: news@CS.UCLA.EDU
Reply-To: casey@cs.ucla.edu (Casey Leedom)
Organization: UCLA Cognitive Science Program
Lines: 33


| From: krowitz@richter.MIT.EDU (David Krowitz)
| 
| Just out of curiosity ... what was the error message that lead you to
| suspect the electronics on the drive and not the HDA? Every time we've
| had a drive fail, it has turned out to be the HDA (of course, they
| weren't 5 1/4" drives, they were the MSD-167 in the DN460/660 or the
| MSD-500 in the DSP-80).
| 
| Actually, come to think of it, when our MSD-500's failed (three of them!),
| one of the things they did try was swapping the electronics on the drive
| ...  which they did after trying a new controller board. Of course, it's
| more of a pain for them to swap out a whole MSD-500 than it is to swap
| out one of the 5 1/4" drives (the MSD-500 must weigh at least 100 lb).

  It was really just a guess.  We hadn't heard any terrible screeching,
etc. and we weren't getting lots of bad data off the drive, it was just
not really there as far as the software was concerned.  It *felt* like a
piece of electronics going away.  I might very well have been wrong, but
as it turns out, I wasn't.

  I also have had an awful lot of experience with maintenance of larger
drives where engineers would come in and swap out various modules of the
drive subsystem.  That's why I was surprised that the Apollo service type
wasn't going to try replacing the drive electronics PCB.

  In any case, they came yesterday and forced me to replace the drive.
I'm really pretty pissed about this because I still think that it was
more superstition than professional opinion on their part.  So now I get
to waste a day reinstalling software and restoring a back up I made the
night before.

Casey