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From: grr@cbmvax.UUCP
Newsgroups: comp.sys.amiga
Subject: Re: Monitor degaussers and Micro Floppies
Message-ID: <1474@cbmvax.cbmvax.cbm.UUCP>
Date: Sun, 1-Mar-87 00:59:21 EST
Article-I.D.: cbmvax.1474
Posted: Sun Mar  1 00:59:21 1987
Date-Received: Mon, 2-Mar-87 04:25:26 EST
References: <847@crash.CTS.COM> <1111@ulowell.cs.ulowell.edu> <560@hao.UCAR.EDU>
Reply-To: grr@cbmvax.UUCP (George Robbins)
Organization: Commodore Technology, West Chester, PA
Lines: 33

In article <560@hao.UCAR.EDU> hull@hao.UCAR.EDU (Howard Hull) writes:
>In article <1111@ulowell.cs.ulowell.edu>, page@ulowell.cs.ulowell.edu (Bob Page) writes:
>> You should check other things.  First is disk quality.  Second is
>> proximity to the monitor degaussing circuits and other electromagnetic
>> fields - tipping the *amiga* up could bring it too close to these
>> circuits.  Other suggestions: air flow (heat problems, dirt),
>> direct sunlight, etc.
>
>Holy Bit Map Batman!  This never occurred to me, and I work with this stuff
>all the time.  Ok.  So how many times can one subject a floppy disk to
>monitor turn-on (Say, with the disk sitting on top of the monitor, fer
>instance) before the disk goes bits-up?

Interesting, but not really the question here.  What can happen is that the
*magnetic* fields produced by the flyback transformer or the yoke in the
monitor can induce currents in the heads or read/write circuitry of the
floppy drive.  This reduces the noise margins and can result in read errors.
Write errors are improbable, but it is not hard to rewrite mis-read data
and thus trash the disk.

The simple way to check for this is to move the drive away from the monitor
or interpose a piece of sheet *steel* between the monitor and the drive.

As have been previously mentioned, the floppy should operate in any
reasonable orientation.  However, a drive that is worn out, out of
alignment or otherwise not quite what it should be might well have a
higher error rate when used in other than the "normal" orientation.


-- 
George Robbins - now working for,	uucp: {ihnp4|seismo|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@seismo.css.GOV
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)