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SPL800
Joined: 10 Nov 2009 Posts: 164 Location: Israel
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Link Posted: Tue Feb 18, 2020 8:12 am Post subject: Barco 1209s sudden chromatic aberration. |
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After watching a movie for about two hours, all sorts of color distortions began to appear in different parts of the picture. Mostly in face scene. and mostly on White bright areas.
i would say there is a problem with the brightness level that is very high. and causing this chromatic aberration
Right now I see a situation where I lower the brightness and contrast to zero and still the image is very bright.
black level still remains on the picture but it looks like very high gain of colors is reaching the tube.
you can see in the pictures marked in black the chromatic aberration mostly on faces scene.
G2 adjustment is ok
17.5v is also ok
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Last edited by SPL800 on Tue Feb 18, 2020 2:15 pm; edited 1 time in total
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kal Forum Administrator
Joined: 06 Mar 2006 Posts: 17850 Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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SPL800
Joined: 10 Nov 2009 Posts: 164 Location: Israel
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Link Posted: Tue Feb 18, 2020 2:16 pm Post subject: . |
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kal wrote: | What projector?
Kal |
Opss my bad its barco 1209s
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garyfritz
Joined: 08 Apr 2006 Posts: 12024 Location: Fort Collins, CO
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Link Posted: Tue Feb 18, 2020 3:06 pm Post subject: |
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[pedant]
Being picky, that's not chromatic aberration. Chromatic aberration is the result of lenses bending different colors (wavelengths) differently. It's a fixed property of the lens, so there's no way it could suddenly show up. What you're seeing is something in the video circuitry.
[/pedant]
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SPL800
Joined: 10 Nov 2009 Posts: 164 Location: Israel
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Link Posted: Tue Feb 18, 2020 7:13 pm Post subject: |
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garyfritz wrote: | [pedant]
Being picky, that's not chromatic aberration. Chromatic aberration is the result of lenses bending different colors (wavelengths) differently. It's a fixed property of the lens, so there's no way it could suddenly show up. What you're seeing is something in the video circuitry.
[/pedant] |
So you would recommend to try to replace the RGB board?
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garyfritz
Joined: 08 Apr 2006 Posts: 12024 Location: Fort Collins, CO
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Link Posted: Tue Feb 18, 2020 8:00 pm Post subject: |
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I don't know. You need somebody who knows that projector -- I don't. I was just clarifying the use of the term "chromatic aberration."
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kal Forum Administrator
Joined: 06 Mar 2006 Posts: 17850 Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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Link Posted: Tue Feb 18, 2020 9:28 pm Post subject: |
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Does it happen on all 3 colours or only one? It's hard to tell from the pics. Throw up some test patterns and see. If only one could be something about one of the neckboards that is causing issues at 100% contrast (or close to 100%) with it clipping/oversaturing and not lowering the signal after.
Then I'd try swapping boards in the video chain.
Kal
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SPL800
Joined: 10 Nov 2009 Posts: 164 Location: Israel
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Link Posted: Tue Feb 18, 2020 9:49 pm Post subject: It’s the RGB video board |
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I replaced the last RGB board that I have from curt (bought 2 in the past lucky me) and problem solved.
Can there be any good reason for replacing 2 board within one week?
Can anyone find what can cause this board to fail so easily?
on the RGB board i disconnected another small board that was attached to it what is this board?
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Hulio
Joined: 15 Apr 2006 Posts: 469 Location: Belgium
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Link Posted: Thu Feb 20, 2020 3:01 pm Post subject: |
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That is R762745 quad decoder+comb filter, part of Barco's proprietary line multiplier/scaler (LiDo, LiMo, LiMo Pro) in later projectors.
Normally, it is not needed for HD signals, only composite video. So could be the reason of your problems, as the comb filter contains the luminance (your high contrast level problem) and chrominance (your colour shift problem) filters.
Probably failing electrolytic capacitors on it, not 105C degree rated.
On the replacement RGB switcher, is also this board mounted ? Remove it from the old board, and see if you still get the earlier problems after 2 hours video watching.
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