[mythtv-users] Refresh line being seen

[MrVining]

On Feb 14, 2009, at 12:58 PM, Paulin wrote:

> On Sat, Feb 14, 2009 at 1:35 PM, Allen Edwards  
> <allen.p.edwards at gmail.com> wrote:
>
>
> On Sat, Feb 14, 2009 at 10:22 AM, Brian Wood <beww at beww.org> wrote:
> On Saturday 14 February 2009 11:02:41 MrVining wrote:
> > On Feb 14, 2009, at 9:26 AM, Paulin wrote:
> > > I'm having an old problem reappear after upgrading the NVidia
> > > driver and then downgrading.  Can't seem to figure it out.
> > >
> > > 1. Upgraded to 180.22 NVidia driver.
> > > 2. Eventually downgraded back to 180.16 driver.
> > > 3. Put the .nvidia-settingrc file back from before the upgrade
> > >
> > > Now whenever watching a recorded program there is a thin line
> > > scrolling down the screen every minute or so.
> > >
> > > Can anyone tell me what I should be looking at to correct this.  I
> > > thought it was caused by the Nvidia settings but since they are
> > > back to what they were before I updated/downgraded the driver I'm
> > > not sure why it's happening.
> > >
> > > Any help would be appreciated.
> > >
> > > Thanks,
> > > steve
> >
> > Is it possible that it is not driver related?  Has there been any
> > physical changes made to the system.  I hear line slowly scrolling
> > down the screen and I still jump right to grounding issue (retired
> > cable guy).
>
> With NTSC at least, a horizontal line scrolling slowly *up* the screen
> indicates 60 or 120 Hz. hum. The rate is the difference between the  
> vertical
> rate being precisely 60Hz, and what it really is with NTSC color  
> (in other
> words, if 3.579545 was in fact 3.600000, then the bar would be  
> stationary).
>
> A grounding issue would thus create a moving up bar, unless the  
> scan rate of
> the video was far enough from 60Hz. to create a downward motion of  
> the bar.
>
> I tend to agree that the OP does not have a driver issue, more  
> likely some
> sort of interference in the machine itself, the monitor, or the  
> cabling, or
> some sort of common mode (ie: grounding) problem.
>
> --
> beww
>
> By ground problem, likely it means that there is a difference  
> between the computer ground and the TV ground.  So, in this case  
> you may not have done anything to the computer but if you plugged  
> the TV in to a different slot or changed your antenna setup it  
> could explain it.
>
> If you have cable, it could even be that the cable guy came by  
> while you were not looking and grounded the feed.
>
> I had to run power from my projector to my surround setup to get  
> rid of a line like that. Now everything is on the same circuit.  I  
> also ground my antenna to that same sub panel.
>
> Allen
>
>
> OK now I'm even more confused.  Sorry :)
>
> Anyway this setup has been this way for a few months (November) and  
> working until yesterday night when I did a few things to the box  
> (removed GNome Network Manager, Attempted to upgrade the NVIDIA  
> driver to 180.22, and rebuilt trunk.
>
> The Myth Box (Backend/Frontend) was not really touched other then  
> to plug in a CRT for some initial work with the Driver setup.
>
> The box is plug into a surge protector power strip that the stereo,  
> TV, DVD and TIVO are all plugged in.  The cable coming in, is split  
> (3-way) and feeds the Tivo, and the two tuner cards in my mythbox.
>
> The line that I have scrolls down only.  When I first configured my  
> MythBox I had this issue and it was fixed when I got the NVidia  
> settings correct.  That may have been a cooincent.
>
> If fixing the grounding issue what part should I look at changing.
>
> Thanks and sorry for my ignorance.
> steve

My method for trouble shooting grounding problems was to remove as  
many things from the equation as possible (everything connected to TV  
or computer).  Use the computer to playback a recording, if the bar  
is gone, reconnect your equipment one by one and watch for the bar to  
come back.
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