Mailing List Archive

At 10:22 AM 5/2/2003 -0600, Alexander P. Petkov wrote:
>TV-tuner card is Avermedia TV98 w/remote.
>
>I can't watch TV through the tv-tuner card anymore, because the video
>has lots of diagonal lines, and the sound frequently disappears
>altogether.
>
>It started having a lot of picture noise (lots of diagonal lines) and
>dropping sound during a scheduled MythTV recording session (the
>problem 1st occurred within that recording). Every consecutive
>recording has garbled picture and choppy sound. The file size is also
>over twice as big as it what it should be (around 900MB vs the usual
>370 MB for a 1/2 hour recording).
[rest deleted]

The larger file size is typical behavior for any codec when the image gets
noisier. To the codec, a noisy signal is just a more complicated one, and
it tries to encode the noise as best it can. So put that part of your
concern aside and address the core problem.

Diagonal lines? This is hard to diagnose, because it can mean many things.
This morning, on a vidcap system I have here, I saw dark diagonal lines
moving systematically across the screen. It lowered the quality of the
video by a lot, but it did not make it unviewable. Still, it was a problem.
I tracked it down to my having moved cables around last night, so that the
coax cable feeding the system was running close to a power bar. When I
moved the cable, the problem went away. So I infer it was some sort of 60
Hz interference, either from the power line itself or from the surge
protector in the power bar.

I cannot say that this is your problem, of course. I did note that your
troubleshooting report omitted any discussion of the cabling, though, so I
don't know if the various moves involved changing or moving the cables.

If it is not, though ... I can say that diagnosis would benefit from a more
exact description of the type of interference you are seeing. Or maybe a
jpeg of it would clarify things (is there any reasonable way to provide a
diagnostic image by way of this list? if not, might we all benefit from
ading some such mechanism?).

>Or maybe a jpeg of it would clarify things.

Definitely, I will do that tonight and provide you with a link. I
understand your explanation about the encoding process and the resulting
file size increase, it makes perfect sense.

As far as moving the cables, I had the whole computer at a different
location in the apartment. The problem was still there. I will try moving
the cables around as you suggested though. At this point I will try anything.

It seems that the problem is not the tv-tuner card itself. Otherwise why
would it work fine in one machine and not another? Can it be deffective,
but not really?

Thanks for your suggestions,
Alex

Try shielding your card with aluminum foil grounded to your case... just
make a cardboard box that will surround your card without touching it
and line it with foil in all the places that the foil wont come in
contact with anything and connect the foil to the computer's case... I'm
not gonna guarantee that this will help but it might reduce emissions
caused by components within the case. Also make sure you are using
RG-6 coax cable (assuming your in the us) instead of the standard and
lightly shielded RG-59 to help reduce interference with the cable
itself.

Computer cases are generally pretty noisy (electronically speaking) and
they can often cause interference. The reason that your composite input
might be cleaner is that the electronic interference might not be of the
right frequency to disrupt composite video.

Joe

Just my 2 cents, take them for what they are worth... practically
nothing.

-----Original Message-----
From: mythtv-users-bounces@snowman.net
[mailto:mythtv-users-bounces@snowman.net] On Behalf Of Alexander P.
Petkov
Sent: Friday, May 02, 2003 12:23 PM
To: mythtv-users@snowman.net
Subject: [mythtv-users] TV-tuner signal interference problem

TV-tuner card is Avermedia TV98 w/remote.

I can't watch TV through the tv-tuner card anymore, because the video
has lots of diagonal lines, and the sound frequently disappears
altogether.

It started having a lot of picture noise (lots of diagonal lines) and
dropping sound during a scheduled MythTV recording session (the
problem 1st occurred within that recording). Every consecutive
recording has garbled picture and choppy sound. The file size is also
over twice as big as it what it should be (around 900MB vs the usual
370 MB for a 1/2 hour recording).

Also, now when I watch regular (live) TV with xawtv, the video
interference and sound problem is persistent. Even when I boot into
Windows, the problem is there.

When I switch to composite (to use the VCR's tuner), the picture and
sound is normal. So that eliminates cable reception problems. This
leads me to believe that the problem is hardware related.


These are the things I tried in order to solve it:

1. I removed the TV-tuner card and installed it in a spare machine.
The result--video and sound were clear when using the card's on-board
TV tuner. So I think that the card itself is not defective.

2. I put the card back in the original machine, the problem of course
came back.

3. I removed the computer from its' current location (away from other
equipment), tried watching live TV, the problem is there. So it has
to
be something within my computer causing the interference.

4. I changed the power supply, it was getting hot actually. The
problem did not go away.

5. I removed every other card, except the tv-tuner card and graphics
card. Nothing was plugged into the tuner card except the composite
cable. No improvement.

6. I moved the tv-tuner card as far away as possible from the
graphics
card, the problem is still there. Although the pattern of the video
noise changes.


All this leads me to believe that the tv-tuner card itself is not
defective, but I have interference problem within my computer. The
spare machine is only P233 MMX, so using it for a myth PVR box is not
an option.

What else could be causing the garbled video and choppy sound? I am
out of ideas. Besides posting to the forum, it looks like the only
other thing I could do is call Miss Cleo.

It would be easy if the card didn't work well in another
computer--then I would just change the card. But now, even if I go
and
buy another one , it looks like the problem will persist.

Do you have any ideas as to what can fix this? The only things I
haven't removed are memory, processor and peripheral HD and CD-ROM
drives.

I can't go back and watch TV without Myth. I simply can't. I won't!!

If needed I can grab some screenies to better illustrate the problem.

Any ideas are appreciated, thanks in advance.


Alex

_______________________________________________
mythtv-users mailing list
mythtv-users@snowman.net
http://lists.snowman.net/cgi-bin/mailman/listinfo/mythtv-users

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Fri, May 02, 2003 at 11:42:30AM -0600, Alex Petkov wrote:
> >Or maybe a jpeg of it would clarify things.
>
> Definitely, I will do that tonight and provide you with a link. I
> understand your explanation about the encoding process and the resulting
> file size increase, it makes perfect sense.

I obviously cannot speak for others, but JPEG is jut about the worst format
to be trying to show off video problems. You'ld have better luck with PNG
probably.

Jeff
- --
- ----------------------------------------------------------------------------
Computer Science is as much about computers as astronomy is about telescopes
-- Edsger Wybe Dijkstra (1930-2002)
- ----------------------------------------------------------------------------
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.1 (GNU/Linux)

iD8DBQE+sq+AXazNjIaibJERApQSAJ0b3dtV7bZt9Oi1AHzNASJapDJk3gCeOthi
uVPHmlTEUBEd23tZ8LI5e0Y=
=F10P
-----END PGP SIGNATURE-----

At 11:42 AM 5/2/2003 -0600, Alex Petkov wrote:
> >Or maybe a jpeg of it would clarify things.
>
>Definitely, I will do that tonight and provide you with a link. I
>understand your explanation about the encoding process and the resulting
>file size increase, it makes perfect sense.
>
>As far as moving the cables, I had the whole computer at a different
>location in the apartment. The problem was still there. I will try moving
>the cables around as you suggested though. At this point I will try anything.
>
>It seems that the problem is not the tv-tuner card itself. Otherwise why
>would it work fine in one machine and not another? Can it be deffective,
>but not really?

I would be surprised if the problem were the card, given what you say. But
I'm no electronics hardware expert, so sometimes I do get surprised.

One other thing I have noticed is that card noise is sensitive to the
location of the card in the PC. I've settled on always putting a vidcap
card in the pci slot located farthest from the CPU ... which in my
experience is always the leftmost (viewed from the front) pci slot. I've
seen a lot more noise (in the form of vertical bards, though, not diagonal
lines) if I place the card near the CPU.

I had this same exact problem with the first machine I
tried using for mythtv. Never figured out what was
causing the problem either :/

--- Jeffrey Brent McBeth <mcbeth@broggs.org> wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On Fri, May 02, 2003 at 11:42:30AM -0600, Alex
> Petkov wrote:
> > >Or maybe a jpeg of it would clarify things.
> >
> > Definitely, I will do that tonight and provide you
> with a link. I
> > understand your explanation about the encoding
> process and the resulting
> > file size increase, it makes perfect sense.
>
> I obviously cannot speak for others, but JPEG is jut
> about the worst format
> to be trying to show off video problems. You'ld
> have better luck with PNG
> probably.
>
> Jeff
> - --
> -
>
----------------------------------------------------------------------------
> Computer Science is as much about computers as
> astronomy is about telescopes
> -- Edsger Wybe Dijkstra (1930-2002)
> -
>
----------------------------------------------------------------------------
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.2.1 (GNU/Linux)
>
>
iD8DBQE+sq+AXazNjIaibJERApQSAJ0b3dtV7bZt9Oi1AHzNASJapDJk3gCeOthi
> uVPHmlTEUBEd23tZ8LI5e0Y=
> =F10P
> -----END PGP SIGNATURE-----
> _______________________________________________
> mythtv-users mailing list
> mythtv-users@snowman.net
>
http://lists.snowman.net/cgi-bin/mailman/listinfo/mythtv-users


__________________________________
Do you Yahoo!?
The New Yahoo! Search - Faster. Easier. Bingo.
http://search.yahoo.com

I believe I have found what's causing this video signal
interfererence
with my tv-tuner card.

I am running an Abit BH6 ver 1.0 with an upgradeware slot-t adapter
that houses a Celeron 1.4 precessor.

Anyway, I took the whole machine apart this morning, and inspected
cards one by one.

1. I changed the video card, the video noise problem was still there.
2. I changed the processor with an old Celeron 400Mhz, the problem
almost went away.

Upon closer inspection of the motherboard, I see that the inductor
coil (between the keyboard and PS/2 mouse ports, and the slot 1) is
all charred.

Also, the 4 capacitors at the same location are swallen and cracked @
the top.

What happens is that the Slot-t adapter supplies voltage through the
molex connector, which is out of spec for the motherboard. People
suggest an aluminum plate to dissipate heat, but I didn't have one.
Other than that, the motherboard works fine.

I tried again the tv-tuner card in another computer, no problem
whatsoever with the signal.

So , it looks like I will have to look to change/upgrade the
motherboard, ot try to fix it.

Any suggestions for a Tualatin motherboard? Is it possible to replace
the coil and capacitors on the Abit?

Thanks for reading this and for your ideas,

Alex

QUOTE:
=========
If so, you should probably pursue this failure with Abit, since I'd
expect that the mobo manufacturers casre enough about their
reputations that they will scurry to make things right with the
victims of this problem (they were doing a lot of spin control at the
time the news broke). I know my son, who had a mobo with the bad-cap
problem, got a quick replacement -- not for free, but for cheap --
from their local office. At the moment, I cannot recall if his was an
Abit or not.
=========

Ray:

I am afraid the swollen caps are my own doing. I ran the BH6 with a
slot-t adapter and people report that there is a real danger of this
happening. Well, the board is fine and works (don't know for how
long), but my poor TV-tuner doesn't like it one bit.

Also, people that pursued the motherboard replacement as you
suggested
were denied by Abit, they would only repair out of waranty mobo for
money.

Anyway, now I am looking at either trying to repair the caps and
coil,
or to replace the motherboard with one that has Tualatin support.

Any suggestions for such a board? it seems to me that is a dead end
as
far as upgrading it in the future. On the other hand it is the most
budget-oriented solution for now.

So, I am trying to decide if I should attempt a repair, or change the
mobo, and if I change it, with what.

Any ideas are appreciated.

Alex

What ever you do... I'd stop using the board... the caps and coil are
your filters for the processor (as I'm guessing you know) and unrefined
DC can not be good for a processor.

Joe

This is just my 2 cents.. take em for what they are worth.. pretty much
nothing.

-----Original Message-----
From: mythtv-users-bounces@snowman.net
[mailto:mythtv-users-bounces@snowman.net] On Behalf Of Alexander P.
Petkov
Sent: Sunday, May 04, 2003 1:56 PM
To: mythtv-users@snowman.net
Subject: [mythtv-users] Re:TV-tuner signal interference problem

QUOTE:
=========
If so, you should probably pursue this failure with Abit, since I'd
expect that the mobo manufacturers casre enough about their
reputations that they will scurry to make things right with the
victims of this problem (they were doing a lot of spin control at the
time the news broke). I know my son, who had a mobo with the bad-cap
problem, got a quick replacement -- not for free, but for cheap --
from their local office. At the moment, I cannot recall if his was an
Abit or not.
=========

Ray:

I am afraid the swollen caps are my own doing. I ran the BH6 with a
slot-t adapter and people report that there is a real danger of this
happening. Well, the board is fine and works (don't know for how
long), but my poor TV-tuner doesn't like it one bit.

Also, people that pursued the motherboard replacement as you
suggested
were denied by Abit, they would only repair out of waranty mobo for
money.

Anyway, now I am looking at either trying to repair the caps and
coil,
or to replace the motherboard with one that has Tualatin support.

Any suggestions for such a board? it seems to me that is a dead end
as
far as upgrading it in the future. On the other hand it is the most
budget-oriented solution for now.

So, I am trying to decide if I should attempt a repair, or change the
mobo, and if I change it, with what.

Any ideas are appreciated.

Alex

_______________________________________________
mythtv-users mailing list
mythtv-users@snowman.net
http://lists.snowman.net/cgi-bin/mailman/listinfo/mythtv-users

> From: "Joseph H. Fry" <joe@thefrys.com>
> What ever you do... I'd stop using the board... the caps and coil are
> your filters for the processor (as I'm guessing you know) and unrefined
> DC can not be good for a processor.

Besides, motherboards are SO cheap! $59 for a new mobo (delivered 2nd day)
from googlegear.com, or unsoldering and replacing caps and coils, with a
chance of frying your processor? That would be a simple choice from my
end...

Cheers!
JC

Thank you all for your suggestions.

I would like to attempt the repair, but I would be afraid to let it
running while I am out during the day. It looks like a new tualatin
mobo would work, just for piece of mind's sake.
Now I am looking at the Soyo SY-TISU.

I think I would replace the caps on the Abit just for the heck of it.

Alex

I finally got a new mainboard.

I replaced it, the video noise dissapeared, picture quality is back to normal.
So the capacitors on my Slot 1 BH6 motherboard were the culprit.

The problem now is that my linux HDD appears to be really slow (10G Western
Digital, ext3 on it). The whole OS is kinda slow to respond. My FAT32 drive
(where i record) reports approx 34 MB/sec drive reads, while my Linux disk
reports approx 13 MB/sec. DMA enabled on both. I also have gbuffers=16.

Hmmm, gotta look into it.

At least I'm back to being a Myth user. 2 painfull weeks without Myth
finally over!!!


Alex