HELP with 7300 hard disk PLEASE

[Thad P Floryan]

The following two items weren't cross-posted to unix-pc.general; I've included
them for their technical and entertainment value.

====================

From: jbm at uncle.UUCP (John B. Milton)
Newsgroups: comp.sys.att
Subject: Re: HELP with 7300 hard disk PLEASE
Date: 1 Nov 88 05:02:51 GMT
Organization: Just me and my computer, Columbus Ohio
Lines: 35
Keywords: dead disk 7300 help

In article <1311 at plx.UUCP> walt at plx.UUCP (Walt Novinger ) writes:
>My 7300's 40MB Seagate ST251 hard disk suddenly went south the other day,
>and I have to get the data off it, if possible.  I tried running the
>diagnostics disk to test the drive, and it fails on the "recal" test.

Are you absolutely sure it's spinning up? I have heard of drives where the
baking mechanism stickes to the spindle on shutdown and the next time you
power it up, it won't spin up. If it won't spin up, it won't try to move the
heads. One solution was dropthe fron of the machine about 6" to jar it loose.
I don't think I would recomend that. If it is spinning up, then the lack of
recal could be several problems.

Bad logic board on the drive. You should be able to get that board replaced and
still get the data. BE WARNED if you try to send a drive back for service, even
if you mark it to keep the drive part, they will most likely scrap it. The best
solution is to get another drive of the same type, a spline head tool and swap
the board yourself.

The other thing keeping it from recaling might be soft. The diagnostic disk
won't tell you the difference between 1. can't move the head to track 0,
2. can't get a track header on the lowest track, and 3. drive is missing the
drive magic number. It could be that a tiny glitch has dinged the VHB (Volume
Home Block). The bad news is that there isn't much in the way of low level
utilities on the UNIXpc to go patching around with. The interactive device
test is supposed to almost allow some of this, but it won't work for hard disks,
only floppies. My suggestion if you want to see what's REALLY on the disk right
now, is to put it on a PClone and get ahold of one of those super fantanstic
hard drive programs that are out now. One of those should be able to show you
more than you want to know and, at least tell you whether it's a hardware or
magware problem.

John
-- 
John Bly Milton IV, jbm at uncle.UUCP, n8emr!uncle!jbm at osu-cis.cis.ohio-state.edu
(614) h:294-4823, w:764-4272;  MS-DOS is a beautiful flower that smells bad!

====================

From: thad at cup.portal.com (Thad P Floryan)
Newsgroups: comp.sys.att
Subject: Re: HELP with 7300 hard disk PLEASE
Date: 1 Nov 88 09:43:22 GMT
Lines: 66

Walt Novinger is having problems with his Seagate ST251 ...

Welcome to the club.  But, one question: does the drive SPIN?

Don't laugh.  I have a bunch of ST251 drives that do NOT spin up consistently
and the first time that happened I started sweating icicles.

My first thought was a "bad" controller card (the one that is bolted to the
back of the drives), and I called Seagate Customer Support (in Florida; figure
that one out) and discovered that all Seagate does is exchange drives.  Not
very useful if you want to retrieve data that hasn't been backed up (let THAT
be a lesson!).  Finally, persevered and managed to reach the Manager of QA at
Seagate in Scotts Valley, CA, and was told essentially the same story: they
don't repair drives, wouldn't send me a PC card, and they don't have spare
parts.

By this time, I had already discovered the drive wasn't spinning up.

Being the curious sort, I started examining all aspects of the drive.  Poked
here, prodded there, uttered a few choice epithets, and was seriously
considering the sure-fire-cure: dancing under a full moon in my Jockey shorts
while swinging a dead chicken over my head!  :-)

Well, to make a long story short: I started idly twisting the stepper motor
shaft using an Allen wrench, about 15 degrees each way.  Decided to attempt to
power up the drive one more time before chucking it out the window and over
the fence when, LO!, whi-r-r-r-r-r-r.  It SPUN!   Twisted the shaft of another
one, powered it up, and it, too, spun.

Whew!  Did I back up those disks quickly.

First thing next morning, called Seagate (Scotts Valley) QA Manager and
discussed my findings.  An engineer was consulted and confirmed that the
ST251 drive has "failsafes" to prevent main spindle rotation IF the arms
don't come out of `park' during the power up sequence.

My "twisting" the stepper motor shaft a bit must have loosened up whatever
it was that prevented the arms coming out of park.  Don't know what, since
the drives are normally powered 24 hrs/day, 7 days/week, and they were off
for only a few hours while I was experimenting with other aspects of the
system.

NOW: the interesting thing is, ALL of my ST251 have the same date code: 8707
(a big number stamped alongside the frame).  But I've heard in other newsgroups
of others having problems with the ST251 also, and the solution was the same
"fix."

BE FORWARNED: the "fix" is only temporary.  The ones I still have continue to
exhibit the problem occasionally upon power up.  Once the drives are spinning,
they operate fine.  But I'm really disappointed about these problems and have
switched almost exclusively now to other manufacturers (e.g. Maxtor) though
I am having excellent performance from an ST157N.

As near as I can determine, the problem ONLY exists with the ST251-0  (the
"-0" is often identified by an "MLC-0" sticker); the ST251-1 (also MLC-1)
drives don't (yet) appear to have such a problem (but perhaps it's too early
for the problem to surface).  For reference: the MLC-0 drives are the 39mS
ones and the MLC-1 drives are the 28mS ones.

SUMMARY: twist the stepper motor shaft a wee bit using a dowel, screwdriver,
Allen wrench, whatever), power up the drive and get your data off it ASAP.
As mine have shown, the drives will continue to present problems, so I'd
suggest looking for a replacement HD before yours fails totally.


Thad Floryan [thad at cup.portal.com (OR) ...!sun!portal!cup.portal.com!thad]