*BSD News Article 90707


Return to BSD News archive

Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!news.ecn.uoknor.edu!news.wildstar.net!news.ececs.uc.edu!newsxfer.itd.umich.edu!newsxfer3.itd.umich.edu!howland.erols.net!vixen.cso.uiuc.edu!saluki-news.it.siu.edu!slip106.termserv.siu.edu
From: jimd@slip106.termserv.siu.edu (Jim Dutton)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: wavy video under X ?
Date: Mon, 10 Mar 1997 01:52:27 CST
Organization: Southern Illinois University
Lines: 33
Sender: NNTP@slip106.termserv.siu.edu
Message-ID: <24172a57.u9t27e.3d095@slip106.termserv.siu.edu>
Reply-To: jimd@slip106.termserv.siu.edu
NNTP-Posting-Host: slip106.termserv.siu.edu
Comment: AmigaNOS v2.9p
In-Reply-To: <33237BD3.2781E494@w2xo.pgh.pa.us>
	     (from Jim Durham <durham@w2xo.pgh.pa.us>)
	     (at Sun, 09 Mar 1997 22:11:15 -0500)
Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:36826

Hi Jim, on Mar 09 you wrote:

> My guess is that it is a hardware problem. If the software worked at
> first,
> then it should work now.
> 
> The most likely thing is hum in the monitor's power supply. This has
> a frequency of 60hz. If your monitor's vertical scan rate is, say, 65hz,
> you will get 5 "waves" per second (the difference of the 60hz hum
> frequency and the vertical scan frequency.
> 
> A tip-off to this is that you can have slight horizontal "stripes"
> rolling
> through the picture also, moving usually from bottom to top.
> 
> My advice...if you have electronic skills, check the power supply in
> your
> monitor. If not, try another monitor. If it works OK, send yours in for
> repair.
> 
> I doubt it's XFree86. Changing the scan rates in the X config
> (by the way, it's /usr/X11/lib/X11/XF86Config ), may change the
> frequency of the "wave", but probably won't eliminate it.

Oh, I KNOW that it is the hardware. Even in "system console" mode (no X),
there is a noticable "wave". The XVidtune adjustments have made the various
screens more stable.

While I have seen the types of 'stripes' that you mention on other monitors,
they haven't yet appeared on my FreeBSD/Gateway-2000 monitor. Now a power
supply that is showing stress is interesting. I will have to scrounge around
for another monitor, I guess.