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From: npollack@polyslo.UUCP (Neal Pollack)
Newsgroups: net.micro.pc
Subject: Re: Hard disk shut-down (really terminal fires)
Message-ID: <220@polyslo.UUCP>
Date: Mon, 27-Oct-86 23:35:52 EST
Article-I.D.: polyslo.220
Posted: Mon Oct 27 23:35:52 1986
Date-Received: Tue, 28-Oct-86 21:37:11 EST
References: <302@neoucom.UUCP> <2475@gitpyr.gatech.EDU> <1379@kitty.UUCP>
Organization: Cal Poly State Univ,CSC Dept,San Luis Obispo,CA 93407
Lines: 58
Keywords: computer on, but monitor off please
Summary: Re: Hard disk shutdown & fire safety



In article <1379@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes:
>
>	There is nothing in a CRT monitor which is any more prone to catch
>fire than in a computer itself.
>	CRT monitors have no more than 24 volts DC present in any circuit
>element, with the exception of the high voltage accelerating potential
>circuit.  Now, THAT circuit may well have 12 to 25 kilovolts of DC, but will
>be so current-limited (a few microamperes), that one would be hard-pressed
>to start a fire by intentionally removing the anode wire and arcing it between
>ground and a piece of paper!
>	What else is there _different_ in a CRT that will burn?  The
>deflection yoke?  No way!
>
>==>  Larry Lippman @ Recognition Research Corp., Clarence, New York
>==>  UUCP:  {allegra|decvax|rocksanne|rocksvax|watmath}!sunybcs!kitty!larry
>==>  VOICE: 716/688-1231           {hplabs|ihnp4|seismo|utzoo}!/

No offense Mr. Larry Lippman, but you are giving users dangerous
advice indicating that it is not realistic for a monitor to cause
a fire.  I have been a technician for 12 years, and an Engineer
for the last 7.  I have seen numerous fires started by both 5 volt
logic, and high voltage in monitors.  Netland people, do not fear
your low voltage logic, it is rare to start a fire with the 5 volt
levels.   However, when it comes to the monitors, maybe Mr. Lippman
can explain to our Fire Department why he thinks they can not burn.
We have seen several monitor fires here over the last few years.  They
have ranged across many brands.  In most cases, the high voltage
section (10 -25 Kvolts) has started a fire by either arcing or
internals shorts in the transformers. In one case, a power resistor
in the power supply of a Tek Graphics terminal flamed out and set
the board on fire overnight.  In all cases, our smoke
detectors alerted the fire crews before serious damage to the
laboratory complex.  Larry states, "you may be hard-pressed to
ignite a piece of paper...". I say, and have seen, that you
can easily destroy the entire terminal
and maybe the building which houses it.   The problem usually starts
with a build-up of combustible dust, attracted by electro-static
charge.  The dust may absord moisture, which can then result in
arcing.  The arcing WILL cause the dust to burn, and hence the
transformer and insulation will follow.
Also, beware of people at your site that toss print-outs on top
of a monitor (right over the cooling vents).  Very expensive
mistake if you don't like modern char-black wall-paper.

Moral:  Leave logic and hard-disk on.
        Turn monitors OFF !!

This is the policy in our lab units.

(P.S.  Larry, I do not hate you, I just happen to be a safety type.)

Neal Pollack   
Chief Engineer
California Polytecnic State University
Computer Science Department
San Luis Obispo, CA  93407