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From: firstname.lastname@example.org (milne_v)
Subject: Re: Disk drive handling in assembly
Date: 4 Oct 2002 05:49:59 -0700
References: <3D9CF7A9.BF4BB1C0@webaccess.net> <email@example.com> <3D9D1517.F9300485@webaccess.net>
NNTP-Posting-Date: 4 Oct 2002 12:49:59 GMT
Chuck Simmons wrote in message news:<3D9D1517.F9300485@webaccess.net>...
> The little lost angel wrote:
> > On Fri, 04 Oct 2002 02:06:54 GMT, Chuck Simmons
> > wrote:
> > >day. The motive for this question derives from a question about high
> > >failure rate experienced by a particular company. I have already given
> > IBM?? :D
> No. Nobody at IBM ever asks me anything. That's probably wise of them.
> > >Does the final product provide for appropriate cooling air for the head
> > >disk assembly and the electronics board mounted to the head disk
> > >assembly?
> > Could it be the environment the HDD are used in?
> I was asked to consider this issue because I have 20 years experience in
> the hard drive business. Since, at this point, the whole thing is a
> favor for an old friend, I consulted another hard drive engineer with 30
> years experience who I know. We independently concluded that the most
> probable problem is handling and probably hard work surfaces or forcing
> drives into mounts with tools. Both guarantee high failure rates at
> least in our combined experience at several companies spanning a lot of
> disk drive history. ESD is probably second to mechanical abuse as a
> cause of high failure rates. I put environment at the bottom of the
> list, in this case, because the statistics do not deviate with geography
> (wide spread sites).
> My questions are in top to bottom order of likelyhood of causing field
> failures at a moderate but constant rate.
After spending many years assembling computers and servicing returns,
there are several factors I noticed over the years. The odd time, bad
drives came in batches as was the case some years ago with a large lot
of Compac machines and Quantum hard drives. Some various products may
actually be grey market components which I also saw a lot of. Some
manufacturers products were simply better than others, and I
experienced a higher failure rate with certain manufacturers,
especially if it was a newer capacity drive. Then came the matter of
drive mounting. If the bays were somewhat too large where the drives
mounting screws forced the body outwards then you could have problems
later on. If the mounting screws were too long then the screw might
butt up against a circuit board inside or something similar, this
could cause the death of a lot of drives. Drives should be handled
with some attention to ESD prior to installing in the case and some
care should also be taken when attaching or removing cabling. Cabling
(power/data) should also not put any undue stress on the drive. This
can be accomplished by putting a short bend a few inches out from
where the cabling connects to the drive. Cable ties also help to
reduce cabling vibration on the drive, especially if the computer is
being moved around quite a bit. Finally, as a general rule of thumb,
do not mount the drives up side down.
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