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Streaking / Ghosting on BD 701s

Discussion in 'Projectors, Screens & Video Processors' started by Morten, Oct 6, 2003.

  1. Morten

    Morten
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    Hello...

    This is my first post on this forum.
    I've searched and searced for any solutions on my problem but did not find any.
    A "little bird" whispered me that I might get answer on this problem here. Maybe Roland@B4 are familiar with this problem?

    I guess its whats called streaking.
    What I typically see is when a dark item is in contrast to a lighter one, it creates a shadow on the light, and this is only to the right of the dark item...
    I've tried thing like shifting image, different syncs, different resolutions, different cables ++...
    but its the same, no matter what :(

    The problem is only on RGB inputs. On video its fine, but the internal linedoubler creates LOTS of noise on picture if on.

    I have also some Halo rings, but these are not nearly as big a problem! Barely never show.

    Otherwise I am very satisfied :)

    Hope anyone are familiar with and maybe have some tips about this streaking...!

    Thanks.

    Morten.
     
  2. Roland @ B4

    Roland @ B4
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    I have a module going through production at the moment. Your post has reminded me to chase them.
    This effect is caused by a bandwidth problem in the RGB amplifier (the bit that is right on the end of the tube). Mostly it is visable what a near black background has some bright highlights the image then straks across the screen from the highlight to the right side of the screen (ceiling or floor its the same).
    I don't have a final cost yet but looking to be in the £100 - £150 for a set of sub boards to do all three tubes. It will need a bit of soldering but should not require the complete removal from the projector.

    The Dark streaking on white backgrounds will more than likely be ringing and I wouldn't mind betting you are using a PC or scaller above line doubling or tripling.
     
  3. Morten

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    Thank you for your reply!

    I am not sure if streakign is my problem then...

    I might just have this ghosting, and I now suspect its something on my signalway/cables!

    I am using a small barco interface. It has one short hd15male cable connected, and also a female connetor input. And of course RGBS bnc out... No settings. Only powerbutton.
    I tried experimenting with different cables yesterday.
    And what I noticed is than when using the inteface and with my monitor connected through the female connetor on the interface I get more ghosting than without. Also without monitor I get a VERY bright image! TOO bright. It's so bright that I actually get too much light to correct it with brightness/contrast-settings! I have to turn it down on the pc too, to even get the image sharp.

    I also have an older lower quality hd15 to 5bnc cable. I tried this, but this one only gives lots of noise and problems with the image!

    hiqual cable:
    [​IMG]
    [​IMG]

    I shall get a HD15 to 5bnc female, and try connecting with my hiquality cable. Hope this will get better...
    This will for sure eliminate any problems I might have with the interface, and also noise coming in to the cable...

    *crossing my fingers*

    I'll get back when tested some more.
     
  4. Roland @ B4

    Roland @ B4
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    I doubt this is a cable issue.
    On the Barco interface there are some dip switches for setting the termination and these may be set high infact I know they are because when you unplug the monitor the box is unterminated

    PC resolution should be 800x600 for a 16x9 image Are you running higher than that?
     
  5. Morten

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    I have not noticed any dipswitches on the interface! Actually I am pretty sure they don't exist (externally)

    Also, I've tried different resolutions. I've tried 800x600, 1024x576 and 1024x768.

    Cable are 15meters/50? feet.
    But I guess this should be ok with a cable this long when its really good quality. (I know these cables are used for audietorium installations. )
    and the interface also amplifies, obviously...

    But why am I seeing more ringing with monitor connected to interface.
    The interface seems to be meant to be used with a montitor connected?

    You don't think its event worth trying the cable directly connected to my Radeon 9600 card with sync set to composite?

    I could take some pictures of the inteface, and also the screenshot of the ringing when I get home in the evening...

    At least it doesn't seem to be anything wrong with my pj then :clap:
     
  6. Roland @ B4

    Roland @ B4
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    Is this actually a Barco made interface.?
    It may be one of the really early chaps with 4 LED's that gave the mode it was working in, made of Metal?

    In either case I would try to by pass it now. Your graphics card should have enough push to handle the run you mentioned.
    Either use composite or a "T" peice to combine the syncs. Either way they need to be negative.
     
  7. Morten

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    Its a barcomade interface...
    Like you say a metal one, with 4 leds showing operation mode...
    and powerbotton on front.

    took a picture of it:

    [​IMG]

    Ive also struggled with the 5 years old digital camera to get some pictures that show my problem. I am really sorry that they are of very poor quality! My camera does not want to focus at all with little light and no flash. But you get the idea of what I'm seeing...

    I ended up with this scene from gladiator, when the becoming gladiators are on the move:

    [​IMG]

    Its a typical scene where its very obvious! Light bacground and dark sharp items.
    But the noise are all over the screen, limiting the overall focus and detaling of the picture...

    another example of the problem here, but inverse colorproblem, showing that its not only dark items against white backgrounds:
    [​IMG]
    [​IMG]


    and finaly a one from windows
    [​IMG]


    I WILL try not using the interface. Just right from the radeon with my hiqual cables. hoping this will be the solution.


    A strange thing is that when I used the loqual/cheap cable I have with a 1208s/2 that I borrowed earlier, I did not have any noise on image at all!? Nothing like what I'm seeing with this cable now, and not even like with my new cable and interface...
    Is the RGB input circuit on the 1208 so much better that its not that sensitive to bad cables?
     
  8. Roland @ B4

    Roland @ B4
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    That is the most obvious ringing I have seen for a long time.

    Use the barco box as a door stop but nothing else.
     
  9. Morten

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    Allright...

    now I've tried to connect directly to the computer...

    I now still get some ringing!
    But now its MUCH better!

    I did also try another, good, interface. But this gave to much amplification to the signal.
    So simpler is better...

    I now get the ringing on both sides of dark items in contrast to light ones. But I didn't even get them to show well on pictures:

    [​IMG]
    [​IMG]


    So, I took Rolands advice:
    [​IMG]


    I'll keep testing. I'll try setting the G2, and I'll also try other resolutions, with different porch etc. to see if I can get even more of the ringing to dissapear... :)
     
  10. Morten

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    OH!!

    I just noticed a thing!!

    The scene in gladiator... When they are on the move!
    I do not have any ringing at all!!

    What I am seeing is on the dvd!
    Edge Enhancement!?

    So, then I barely have any noise at all...

    I retried with the interface...
    It has dips for eq... Can compensate for different cablelenghts...
    Found a setting that worked well... But it works just as well without the interface...
    So, then... Im happy! :)

    Roland, thanks for your help!
     
  11. Roland @ B4

    Roland @ B4
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    :cool:
     

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