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From: kopaz@rdlvax.RDL.COM (John 'Echo' Kopaz)
Newsgroups: comp.misc,comp.sys.mac
Subject: Re: Leaving a Mac on 24hrs (power supply)
Message-ID: <112@rdlvax.RDL.COM>
Date: Wed, 26-Aug-87 20:51:38 EDT
Article-I.D.: rdlvax.112
Posted: Wed Aug 26 20:51:38 1987
Date-Received: Sun, 30-Aug-87 06:15:42 EDT
References: <735@ubc-vision.UUCP> <5030001@hpccc.HP.COM> <2693@husc6.UUCP> <4042@utai.UUCP> <5180@ihlpa.ATT.COM>
Organization: Research Development Labs (RDL), Culver City, CA.
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Xref: mnetor comp.misc:1132 comp.sys.mac:6136
In-reply-to: prgclb@ihlpa.ATT.COM's message of 21 Aug 87 13:15:25 GMT

Posting-Front-End: GNU Emacs 18.47.2 of Thu Aug 13 1987 on rdlvax (berkeley-unix)



>The screen is fuzzy for the first several minutes.  Patterns with dots
>close together (like the desktop and the scrolling bars) shimmer, and
>letters aren't very crisp.  After a while, things look okay.

>screen image is not truly centered on the CRT -- it's slightly off
>to the left.  I see the whole image, but there's a narrower "margin"
>on the left side than the right.

>Are these things normal?  I'm going to ask the repair person, but

this sounds to me like a case of EMI!  checking the connections is a good
place to start, but if your power supply is radiating that badly it might 
need to be shielded from the crt.  i would check the specs on the power
supply to see if it has tolerable radiated emissions and maybe do some 
field measurements..... if you have the equipment.  

i think that an inspection of the wiring and connections by a qualified
person is the first step.

for further info on EMI check your freshman physics E&M text.

			.echo
-- 
                        john a. kopaz [aka echo.]
     associate research scientist / software engineer / test specimen
voice: 213-410-1244 -- fax: 213-216-5940 -- corporeal: rdl
arpa : kopaz@rdlvax.rdl.com                            5721 w. slauson ave.
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