Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!ncar!boulder!hartzell
From: hartzell@boulder.colorado.edu (George Hartzell)
Newsgroups: comp.sys.dec
Subject: snow on DECstation 2100
Message-ID: <18826@boulder.Colorado.EDU>
Date: 25 Mar 90 23:43:19 GMT
Sender: news@boulder.Colorado.EDU
Reply-To: hartzell@boulder.colorado.edu (George Hartzell)
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Organization: University of Colorado, Boulder
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Two of the 19" monochrome DECstation 2100s that I support have an
annoying flicker on the screen (6 19" mono 2100's, and one 15" mono
3100 don't have this problem).  One has had it since we opened the
box, and another just developed it.

The flicker is reminiscent of the snow one gets on a PC when writing
directly to the video memory without proper attention to timing.  It
doesn't always happen, sometimes powering the machine down, counting
to 5, and rebooting will make the problem go away.

I have return to factory service on these, so I've been sending parts
back one at a time from the DOA system to try to fix it.  So far I've
sent back (in chronological order) the motherboard, the video ram, and
just last week the power supply.  Replacing neither the motherboard
nor the video ram fixed the problem.  Neither did swapping video
cables with one of my "good" systems.  I really don't think that the
power supply is the culprit, but didn't know what else to try.

Has anyone out there seen this problem?  How did you fix it?

g.

George Hartzell			                  (303) 492-4535
 MCD Biology, University of Colorado-Boulder, Boulder, CO 80309
hartzell@Boulder.Colorado.EDU           ..!ncar!boulder!hartzell