Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!lll-winken!uunet!portal!cup.portal.com!thad
From: thad@cup.portal.com (Thad P Floryan)
Newsgroups: comp.sys.amiga
Subject: Re: Comotose Seagate follow-up & question
Message-ID: <17987@cup.portal.com>
Date: 5 May 89 13:13:16 GMT
References: <5586@cs.Buffalo.EDU> <12584@ut-emx.UUCP> <15369@gryphon.COM> <5640@cs.Buffalo.EDU>
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Organization: The Portal System (TM)
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Re: all the controversy surrounding Seagate disk drives ...

I checked with California Disk Drive Repair Company (Santa Clara, CA) after
they spoke at our AT&T Computer Users' Group meeting (I have 4 UNIXPCs (and
these are 68010, not "PC", UNIX boxes! :-)), and the phenomenon is known as
"white worms" in "the trade" because that's what the excess lubricant on
the disk platters looks like under magnification.

The design flaw is the need for excess lubricant to pass the QA tests.

After a period of use (typically more than 6 months), the lubricant tends to
develop patterns and also tends to congregate in clusters.  When the heads
park, the excessive meniscus literally holds the heads in place preventing
them leaving park position; "failsafes" prevent main spindle rotation when
the heads don't leave autopark position.

The solution (offered by California Disk Drive Repair, and several other
disk drive repair companies in this area) is to remove the Seagate platters
and replace them with regular oxide disks (the Seagate platters are plated
media, which looks like chrome plating; the replacement (non-Seagate) platters
have the "typical" brown color).  Replacement costs range from $60 to about
$120 depending on the drive and the company doing the work.

In my situation with the ten ST251 drives, the drives were typically powered
up for months at a time, then one day (14 months after purchase) they all
started to NOT spin on powerup.  The date code was 8704 (or 8707).

I also have an ST157N, but it's been running now for over 12 months and hasn't
been powered down, so I don't know if this SPECIFIC one has the problem also,
but I've heard from dealers that many do (have the problem).

The problem seems more prevalent with Seagate drives simply because they
(used to?) sell more drives than anyone else, but other companies' drives
have been known to exhibit similar problems.

The actual problem is caused during assembly, when the line workers wipe
the platters too much (with a "cloth" impregnated with a godawful chemical
whose name I hope I never have to spell! :-)    The design specs called for
"one wipe", but the uneven application (by the line workers) caused the
platters to be rejected during optical inspection; the workers, not wishing
to appear to not meeting their quotas, would wipe the disks three, four and
even five times to "lay down" an even (and thicker) layer of the lubricant
(which causes a long-term problem known as "stiction" ... this is when the
heads are figuratively glued to the platter by the lubricant's meniscus when
the heads are parked.

In summary: the solution is to get a replacement drive from Seagate (and
hope for the best), or to replace the platters in the drive with platters
that were not overlubricated.

The blame clearly lies with Seagate re:

1) poor material specification

2) shoddy assembly procedures

3) inadequate QA

But, then, Seagate drives aren't as expensive as Maxtor, Quantum, Conner,
Micropolis and Sony.

And the "funny" thing is, the problem doesn't occur with the "el cheapo"
Seagates using normal oxide media; only with the plated media drives with
super-smooth surfaces, low-mass heads, and excess lubricant.

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