[mythtv-users] HD-3000 recording corruption

[Dawning Sky]

On 4/3/06, Craig Partin <cpartin at gmail.com> wrote:
>
> > > >>>>This is the first time I have been stumped in over two years of
> > > >>>>mythtv
> > > >>>>use.  I got my HD-3000 working just fine tuning QAM stations over
> > > >>>>cable in myth.  The system works flawlessly and reliably except
> that
> > > >>>>QAM recordings get trashed when anything else is happening on the
> > > >>>>system.  It records beautifully when nothing else is
> happening.  This
> > > >>>>happens on all channels, HD and SD.  I can playback 1080i content
> > > >>>>with
> > > >>>>XVMC just fine, even with bob.
> > > >
> > > >
> > > > Sounds like interference getting into the HD-3000 from the video
> card.
> > > > Try moving them farther apart, electrically shielding the card(s),
> and
> > > > make sure if you have a jumper cable between the sound card and the
> HD-3000
> > > > that it is either removed or has RFI protection (a couple of turns
> through
> > > > a torroidal core at each end).
> > > >
> > > > Good Luck.
> > > This was going to be my response too.
> > > Since it is video related it has to be something the video card does,
> > > either as an interference transmission or on the bus. Since it seems
> to
> > > be size related I would not think it would be the bus. It is related
> to
> > > the 'active' area of the screen.
> > >
> > > You might, just to see if that is what is going on, try putting
> > > something between the 2 cards to shield them from each other. A piece
> of
> > > aluminum plate, wrapped in cling wrap to avoid shorting things, would
> > > do. Or for that matter a piece of alum foil between 2 sheets of paper.
> > > Just remember to ground one corner of the shield to the case.
> > >
> > > Geoff
> >
> >
> > My mobo has a communications PCI slot, and I put the HD-3000 there.
> > It also has spread spectrum controls to reduce RFI.  I have switched
> > slots and and toggled the RFI settings and noticed no change.
> >
> > I haven't done the exact test with the video card and signal strength
> > but I cannot watch live TV or azap tune and watch in mplayer without
> > corruption.
> >
>
> Watching Live tv from the HD-3000 and with mythcommflag running in the
> background gives an iowait of ~2.0%.  Nothing else in top looks bad
> nor out of the ordinary.   I don't think this is bus traffic problems.
> I'll break out the tinfoil this weekend and if shielding the card
> doesn't work maybe I can make a nice hat.
>


I would first make sure there is no IRQ conflict, say between HD-3000 and
the sound card.  I used to have similar problems.  After I change the PCI
slots around the problem is gone.  I honestly don't think RF interference is
a big issue here.

DS
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