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From: hogan@rosevax.UUCP (Andy Hogan)
Newsgroups: comp.sys.mac
Subject: Re: Burnt Mac+
Message-ID: <788@rosevax.UUCP>
Date: Wed, 17-Dec-86 18:42:06 EST
Article-I.D.: rosevax.788
Posted: Wed Dec 17 18:42:06 1986
Date-Received: Thu, 18-Dec-86 06:40:14 EST
References: <16644@ucbvax.BERKELEY.EDU>
Organization: Rosemount Inc., Eden Prairie, MN
Lines: 48
Summary: Smoke makes electronics work

In article <16644@ucbvax.BERKELEY.EDU>, dlee@miro.Berkeley.EDU (David Lee) writes:
> 
> About two weeks ago I had an interesting experience with my Mac+.  ...
> The really interesting part came next, about 2 seconds after the screen
> went berzerk my Mac+ started to smoke! I was not imagining this, the distinct
> smell of burnt silicon was present. I finally turned my Mac+ off and the next
> day took it to the dealer to have it fixed (still under warranty). Well, when
> I got there, the dealer plugged in my Mac+ and it went on like nothing 
> happened! So I took it home and have been using it ever since without any
> problems. Now, the thing I have been wondering about is what happened to
> my Mac+ when it smoked? 

All electronic components contain smoke.  This is what actually makes them
work.  All that stuff they teach in schools about electrons, EMF, fields, 
holes, gates, etc. is just smokescreen.  Its the smoke that does it.

If components get too hot, some of the smoke (sometimes a lot of it) can
be let out.  This can happen from shorts, overvoltages, and just plain
wear-n-tear.  Once you let the smoke out, the component(s) don't work the
same.  They need to be replaced with new, smoke-filled components.  (The
non-hermeticity of all electronic component packages allows a very slow
leakage of the smoke at all times, which is why all components, even the
simple resistor, eventually fail.)

All seriousness aside, if your dealer didn't even crack the case just 
because the Mac lit up like it was working, he/she did a really half-ass
job.  If you report smelling burning in any electronic gizmo, a competant
repair person should open it, dismount any and all boards, and examine
*both sides of* each one for crisped components OR board material.  
Under certain odd conditions I have seen components get hot enough to 
desolder themselves, or to blow holes in their DIPs.  Yes, they might
continue to work for a while, but you should insist (especially under
warranty) on a thourough checkout.

Take it back.  If they don't believe you, take it somewhere else. 
Insist on a visual examination and a test with a heavy load on the
power supply.  Once it has been carefully examined and nothing appears 
to be burnt or crispy, you can conclude that you got lucky, and that not 
enough damage was done to cause a problem.  In that case I would install a
screen saver DA and run that sucker 24 hours a day, 7 days a week ,
except for powering up/down if your peripherals allow it, for the rest
of the warranty period.  This would be to push whatever component(s)
did get hot to their limit, forcing any weakness to manifest itself.

-- 
What's a noid?     And why does everyone think I'm two of them?

Andy Hogan   Rosemount, Inc.   Mpls MN