[Coco] Coco Digest, Vol 49, Issue 10

[Paul Fitch]

> Message: 11
> Date: Fri, 3 Aug 2007 21:38:41 -0400 (EDT)
> From: Arthur Flexser <flexser at fiu.edu>
> Subject: [Coco] OT: drive recovery
> To: COCO - Tandy Color Computer List <coco at maltedmedia.com>
> Message-ID: <Pine.SOL.4.21.0708032136360.238-100000 at solix.fiu.edu>
> Content-Type: TEXT/PLAIN; charset=US-ASCII
> 
> Marty comments...
> ---------- Forwarded message ----------
> Date: Fri, 3 Aug 2007 17:29:02 -0700
> From: martygoodman <martygoodman at sbcglobal.net>
> To: Arthur Flexser <flexser at fiu.edu>
> Subject: Re: ever hear of this drive recovery trick?
> 
> It IS odd that no explanation of MECHANISM as to why freezing 
> should do 
> anything good for a stuck drive is provided by the author of 
> this tale, or 
> by the references he alludes to (or perhaps the writer of the 
> tale fails to 
> tell us what his references say on the subject, tho).
> 
> I cannot for the life of me figure how freezing can have any 
> good effect Or 
> why, if it does, it would make data harder to recover later 
> by other means. 
> I don't buy the stuff about "condensation":  The drive is 
> supposed to be 
> VERY hermetically sealed.
> 
> If the drive failes due to a bad controller board, that's 
> something an end 
> user who has some abilty to tinker should be easily able to 
> fix:  Get that 
> EXACT SAME make and model and size and vintage drive, and 
> swap out the 
> controller board.  I've done this on occasion, and on the 
> models I've tried 
> it with it turned out to be rather quick and easy (tho one 
> must have a good 
> set of tools, including often a good set of torx and/or hex 
> drivers, and 
> perhaps of the security sort... all of which I have in stock here.
> 
> But if the problem is a bad motor, that's 'way beyond the 
> scope of even a 
> relatively accomplished tinkerer, for as I understand it 
> "clean rooms" are 
> required when you upen up a drive to the platters, and they 
> may NOT make it 
> easy to pop a platter out and put it in another opened drive. 
>  Never had 
> occasion to try that.
> 
> ---marty
> 
> ************************************
> 
I may be talking out of my A** here, but consider thermodynamics, and the
close tolerances inherent inside a high tech piece of machinery.

The distances involved are milimeters and microns.  Freezing the drive cools
all the metal parts down to 30+ degrees F.  Now anyone who has taken an old
furnace thermostate apart will notice that the copper coil can grow several
inches when heated sufficiently.  And as every guy learns at an early age,
"shrinkage" can occure under cold tempertures<g>.  I suspect that cooling
the drive actually changes the distances between moving parts within the
drive by a significant amount.  Perhaps enough to "unstick" it.