Amiga.org
Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Dazxy2001 on February 14, 2008, 02:07:43 PM
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What causes the screen jitter and occasional artifacts, ie the appearance of fine lines moving up the screen mainly noticable at the edges and moving over icons, when using a scart connection with a crt tv, or lcd tv ? my miggies have always done it, as well as those owned by a friend and is their any solution ? For a machine that is designed for PAL and tv display you would think that a sharp, judder free picture would be do-able! :D
Or, is it just a limitation of the technology ?
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While I have no idea what the technical reason for this is, I can only confirm that I get the exact same thing.
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Never had those artifacts on scart, I always had a rock steady picture.
Maybe get a quality scart cable, cheap ones tend to pickup RFI (http://en.wikipedia.org/wiki/Radio_frequency_interference)
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Guess i`ll need to dig the soldering iron out, the one im using atm was purchased new only a couple of weeks ago :/
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Krusher wrote:
Never had those artifacts on scart, I always had a rock steady picture.
Maybe get a quality scart cable, cheap ones tend to pickup RFI (http://en.wikipedia.org/wiki/Radio_frequency_interference)
I hadn't thought of that. Perhaps I should get a new one. The one I have is a cheap one from around 1990-91 or so.
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But then I wouldn't know its quality until I actually tried it (the new one, that is). Oh well, it's not like it's a major risk.
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I imagine im goin to need to buy a decent cable and chop up the one I`ve just bought for the DB23 Amiga video plug, Ive heard some people say to buy the thicker type as they have better shielding, yet Ive seen those locally for £1 lol, so that doesnt give me much confidence, be helpful if the retailers selling the Amiga to scart used quality components in the first place :)
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If its A1200, I've heard that Alice gets too hot (literally) and heatsink prevents artifacts..
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Hmmm, thanx for that, something to look into, although does the chip run hot over time or is it after a short period of running ? Some people would probably cringe at this as I`ve already seen the comments about heatsinks etc, but I`m goin to be mounting a fan in the case somewhere to have a wee bit of airflow, heat being the enemy and all that, figure if it keeps the motherboard cool it may live longer :)
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I use this for my my A1200: link (http://www.amiga.org/gallery/index.php?n=1895)
But Hodgkinson make a very nice DIY (if you have a laser cutter at home, do it!): link II (http://www.amiga.org/gallery/index.php?n=2291=10)
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I get this with my A1200, its got a built in scan doubler and flat screen monitor.
It doesnt "jitter" but sometimes you can see little glitches hovering in the corners and over icons of the workbench .. ive never really questioned it though ..? :-(
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Krusher wrote:
Never had those artifacts on scart, I always had a rock steady picture.
I get some sort of jitter/twitches on my A600. It's not much, hardly noticeable, but it looks like this:
(http://home.no.net/husq410/twitch.png)
I've learned to live with it. :-)
Maybe get a quality scart cable, cheap ones tend to pickup RFI (http://en.wikipedia.org/wiki/Radio_frequency_interference)
Good idea, I'll inspect the cable and make sure it's properly shielded.
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Scart sux 4ever! RGB Rulez!
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SCART carries RGB, composite video and stereo audio in one cable and has been an excellent way of connecting A/V equipment.
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you could lag the cable with something? that might do the trick.
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monami wrote:
you could lag the cable with something? that might do the trick.
Time to dig the tinfoil out hehe
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rkauer wrote:
I use this for my my A1200:
Looks like a good solution for the heat problem!
Do you have SCART available in South America?
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Is this only related to A600 SCART displays?
I have never experienced this problem on the NTSC, multisync monitor setups on my A1200 or A2000. My old A1000 with an old 1080 is even quite stable.
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SamOS39 wrote:
I get this with my A1200, its got a built in scan doubler and flat screen monitor.
It doesnt "jitter" but sometimes you can see little glitches hovering in the corners and over icons of the workbench .. ive never really questioned it though ..? :-(
So you don't use a SCART connector, do you ?
Then it may be a scan doubling issue, or some technical limitation of the Amiga output that only shows up on some screens. In any case it may be related to the heavy issue I am encountering with my new Samsung LCD monitor (this thread (http://www.amiga.org/forums/showthread.php?t=33955)).
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hardlink wrote:
Looks like a good solution for the heat problem!
Do you have SCART available in South America?
Unfortunately, no. :-(
Only composite and S-VHS.
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In case you see this jitter both on crt & lcd, then it might be interference.
In my case, I have an old 1084s which has been repaired a couple of times (amplification/sound, and display). Then I plugged the A500 with an RGB cable and I noticed those annoying lines . They were more noticeable when the display was shifted to the right using the Horizontal Position , and disappeared when shifted to the left :-?