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From: jeffp@phred.UUCP (Jeff Parke)
Newsgroups: comp.sys.mac
Subject: Re: SE display bug survey results
Message-ID: <1636@phred.UUCP>
Date: Wed, 29-Jul-87 15:35:23 EDT
Article-I.D.: phred.1636
Posted: Wed Jul 29 15:35:23 1987
Date-Received: Sat, 1-Aug-87 01:25:34 EDT
References: <409@sdacs.ucsd.EDU> <1370@apple.UUCP> <421@sdacs.ucsd.EDU>
Reply-To: jeffp@phred.UUCP (Jeff Parke)
Organization: <421@sdacs.ucsd.EDU>o
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d.EDU> wade@sdacs.ucsd.EDU (Wade S. Blomgren) writes:
>In article <1370@apple.UUCP>, ems@apple.UUCP (Mike Smith) writes:
>> Have you put a straight edge of some kind next to the wiggling lines
>> to see how much they wiggle?  If it is measureable, then it would have
>
>As l poster of the survey and the responses, I though I would
>reply to Mike. This same thought occured to me, and I performed the
>'paper test' also. My original SE and the current replacement failed
>miserably. These things Wiggle, with a capital W.  I hate it. I am
>Wade Blomgren
>UCSD ACS
>..sdcsvax!sdacs!wade

I just did the test described, and measured the wiggle at various parts of the
screen to be from 0.005 to 0.008 inches.  I think what makes it
visually annoying is that the wiggles of parts of the screen are out of phase
with each other.  Thus the total displacement of parts of the screen relative
to each other will exceed these measurements.

I can't think of an easy way to quantify that, but I can see qualitatively
little "waves" of wiggle traveling down my screen. This suggests to me some
noise on the CRT steering waveforms (yoke drivers) that is not random and
perhaps at or near a fundamental frequency of the vertical refresh rate.

I have an SE at work and a Mac+ at home.  I sit in front of both of them
(too much) viewing them at similar angles and under similar lighting.  There
is no question that the Mac + display doesn't give this odd kind of wiggle
while the SE does.  Other Mac+ and SE comparisons at work bear this out.


-- 
{ihnp4!allegra!fluke , seismo!rutgers!uw-beaver}!tikal!phred!jeffp {Jeff Parke}
Genie  : JEFFP
DELPHI : JEFFPARKE
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