Newsgroups: comp.sys.mac.hardware
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From: dickie@schaefer.math.wisc.edu (Garth Dickie)
Subject: Re: Centris 610 Video Problem - I'm having it also!
Message-ID: <1993Apr21.020748.4880@schaefer.math.wisc.edu>
Organization: Univ. of Wisconsin Dept. of Mathematics
References: <1qqf6b$oc6@usenet.INS.CWRU.Edu> <1993Apr19.161605.24207@newsgate.sps.mot.com>
Date: Wed, 21 Apr 93 02:07:48 GMT
Lines: 44

horton@what.sps.mot.com (David Horton) writes:
>bm967@cleveland.Freenet.Edu (David Kantrowitz) writes:
>>
>>> When the computer is set for 256 colors and certain operations are done,
>>> particularly vertical scrolling through a window, horizontal white lines
>>> appear on the monitor (which generally but not always spare open
>>> windows).  These lines accummulate as the operation is continued.  If a
>>> window is moved over the involved area of the screen and then moved away
>>> the line disappear from that area of the screen.  This problem is not
>>> observed if the monitor is configured for 16 colors or a 14 inch Apple
>>> monitor with 256 colors is used.
>>>
>>Has anyone NOT had these problems in the given configurations?
>>(that would help eliminate design flaw as the explanation)

>As a data point, I'm using a Centris 610 4/80 with the Apple 16"
>monitor and do NOT have these problems.


I can produce similar artifacts.

I am using a Centris 610 with an Apple 16" monitor.  I got the 8/230/CD
configuration, so there is on-board ethernet and 1 Megabyte of video ram.
The effect only occurs in 256 color and 256 grey modes.  Any vertical scrolling operation, whether with a scrollbar or, say, using vi and inserting lines,
will produce a scattering of horizontal flickering lines on the screen.
They do not persist -- each is visible for perhaps one refresh, and then
that part of the screen is back as usual.

They seem to always start at or about the 64th pixel from the left,
and are maybe 512 pixels wide.  This is certainly not preventing me from
using my Macintosh ;-), but it does seem to be a sign of something
perhaps grounded incorrectly in the video circuitry...


I went ahead and called the Apple Customer Assistance Center, at:
  1-800-776-2333, or 1-800-767-2775 (more direct?)

The person who answered was polite :-).  I also took the chance to complain
about my mouse button sticking, and about the mac hanging on boot after a
(hard - killed MacsBug) crash which left a CD in the drive.  (I had to play
with a paperclip for about 5 minutes to get thing to eject, after which the
mac booted fine.)
-- 
Garth Dickie : dickie@math.wisc.edu
