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Help! Image fault inherant in CRT?

Discussion in 'Projectors, Screens & Video Processors' started by Thunder, Dec 27, 2004.

  1. Thunder

    Thunder
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    Im experiencing a strange effect with my newly set up Barco 808s :confused: (Its my first CRT PJ) When watching digital images especially from a console or some digital animated movies and also in certain scenes on some films horizontal strips or bars of subtle colour change are visible. It seems to be intermitant but can be a little annoying. They seem to trail off of some moving portions of the image such as fish on a blue background in Finding Nemo. In some films such as ROTK no faults are visible throughout the entire film, it seems related to the level of contrast and colour combinations that are being displayed. Is this a characteristic of CRT? a fault with my PJ? or a scaling problem?
    Any Advice would be greatly appreciated, as apart from this niggle the image callibrated by James from crtprojectors is totally breathtaking :D
     
  2. Thunder

    Thunder
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    You should be able to see the effect on these shots, in particular the one withe the whale :(
     

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  3. Erling

    Erling
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    It looks somewhat like 'streaking', which is a known fenomenon with some CRT projectors. However, this is normally brighter, horisontal stripes on either side of bright objects on dark backgrounds. Whether it can also manifest itself as the dark bands seen in your 'whale shot' I dunno. There's really nothing in the image to provoke the wider band below the whale.

    Have you talked to James from crtprojectors about it yet ?

    Cheers,
    Erling
     
  4. Thunder

    Thunder
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    Yep, have been advised that it might be streaking but it tends to appear when there are blocks of solid colour involved :confused: Have E-mailed James at crt and waiting for a reply. Its a real shame because in every other regard the PQ is stunning :(
     
  5. Thunder

    Thunder
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    Heres another shot of the fault :(
     

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  6. Erling

    Erling
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    Took a look at the whale scene on my own Nemo DVD (Reg. 4 PAL Collector's Edition). Could see no trace whatsoever of the problem you're having, despite the 1292 I'm using being sort'a renowned for its streaking...

    Unless its cause and apperance is very different on a Barco, I'm inclined to think your problem must be something else than streaking. Haven't got any other suggestions, except maybe try other cables, other inputs and/or other sources if possible to try and determine where the problem lies.

    Hope you get it nailed one way or another :)

    Erling
     
  7. Godfather

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    I've never seen that 'effect' on my Cine 7LT set up my James. Those scenes in Nemo look fine in my setup at various contrast/brightness settings. Sorry. :(

    Hope you get it sorted.
     
  8. Thunder

    Thunder
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    Ye, its a real pain. Im in contact with James and hes gonna try and pop over to try and figure out whats going on :confused: What Scalers are you guys using?
     
  9. Godfather

    Godfather
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    No scaler. Progressive output straight from a Philips 963SA player.
     
  10. Erling

    Erling
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    No scaler here either.

    An HTPC feeding an Extron RGB 109+ which is then connected to the projector. Extron set at lowest gain.

    Running resolutions of 1440x960 for anamorphic DVDs and 1440x1152 for 4:3 material.
    Refresh-rate either 48 or 50 Hz for NTSC and PAL respectively (I know, very low, but there's no visible flicker during DVD playback and the improvement to the image and convergence drift is considerable, compared to the 72/75Hz I used earlier)

    Playback software is TheaterTek 2.0.

    Best of luck with the solution.

    Erling
     
  11. rigman

    rigman
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    I have the same Tag DVD32R DVD player and Barco G 808s as yourself and I have never seen the banding you are experiencing.

    My scaler is a Rock pro and the image I get is excellent. I have had the set up now for 3 years having upgraded to the pro from a rock + a year ago
    Hope you get sorted out.

    Darren
     
  12. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Just want to point out that this banding is only visible on blue tube. To check whether it's a cable/scaler issue swap G and B BNC's at PJ and see if the fault goes to the G tube

    Gordon
     
  13. Thunder

    Thunder
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    Yep, James himself uses the DVD32R and Barco G 808s :D . The only other possibility is the Lumagen, but Gordon seems convinced that its not. Just in case James is gonna bring his crystalio with him to rule out the scaler problem. If not perhaps its RGB amplifier related :confused:
     
  14. Thunder

    Thunder
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    Good idea Gordon, I will do some experimentation before James visits :smashin:
     
  15. JimmytheSaint

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    Hi Mark

    Just caught up with your thread, now I'm back. I never remember having any banding issues with your projector with any movies (including Finding Nemo), so not sure what it could be (was using Crystalio). Could be a cable issue, but then I would expect to see it on other movies also, so really not sure!

    Yas
     
  16. Thunder

    Thunder
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    Hi mate, hope you had a good time in the US :D Yep, its a really strange problem because apart from that which only seems to happen on certain scenes in certain movies the PQ is absolutely stunning :confused:
     
  17. Thunder

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    May have found the fault, thanks to Gordons suggestion I swapped two of the cables round (blue and green) This seems to stop the problem :) But James is still comin over tomorrow to confirm the diagnosis :thumbsup: It still dosnt make much sense however because if the blue cable is faulty how come the problem dosnt transfer to the green tube when the cables are swapped :confused:
     
  18. Mark Grant

    Mark Grant
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    Hello Thunder,

    Maybe as simple as a dry solder joint at the BNC sockets. (no solder joints on the cable, these are crimped and are robust)

    If it's the cable I will send another or reterminate it, although if fault is only showing on console games and certain DVD's I doubt it is the cable.

    I would try 'wiggling' the BNC connectors at both ends of the cable with the projector running.

    Anything loose will be obvious.

    Maybe try the blue core as a sync, as any problem with sync is more apparent than a problem with colour.

    Also does this get worse when the projector has been running for a long time and is hot? If its OK from cold and gets worse, maybe a failing component or dry joint on a PCB somewhere.

    A lot of possibilities to look at !

    Good luck,

    Mark.
     
  19. Thunder

    Thunder
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    Well, James came today and we seem to have solved the problem :clap: Although the solution was not straight forward :confused: What I discovered last night is that if the blue cable was swapped with the green the problem goes away. It also stayed away when substituting my Belden RGBHV cable for a different one. But when changing my Lumagen for a Crystalio using the original Belden cable in the swapped green/blue configuration, the problem returns :confused: This seems to point to there being a problem with the blue component in my RGBHV cable, but why the problem dosnt transfer to the green tube when swapped over neither I or James could figure out :suicide: So the plan is just to leave the cable in the current blue/green swapped configuration and hope that the problem dosnt rear its head. The only small possibility James could come up with is that if there is a slight fault with the blue cable and my Barco is particularly sensitive to input voltage on blue then that could be the cause :confused: But I just guess its one of those things :D
     
  20. Vince M

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    I dont think this is the crt-I would look at the scaler/settings etc..
     
  21. Thunder

    Thunder
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    Its not the scaler, because as mentioned above we tried James's Crystalio and had the same problem even after trying two or three different resolution/ frequency combinations. Its definately cable/ connection related :)
     
  22. Gordon @ Convergent AV

    Gordon @ Convergent AV
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  23. Thunder

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    Cheers Gordon, Can you tell me any more about the new scaling software being released for the HDP? I saw you mention it another thread :) What should the subjective improvements be? and when is it likely to be available?
    :thumbsup: PS:To be honest on my set up I didnt think the Crystalio looked any better than the HDP :laugh:
     
  24. Gordon @ Convergent AV

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    There will be more accurate 10bit maths done on the scaling. How much of an improvement this is going to give we don;t know until Jim has it finished. They expect to be able to sharpen the image without adding ringing. So hopefully a more detailed 3D image.

    There are also improvements to PAL de-interlacing and the forthcoming addition of film detection for 1080i HD sources. Those should give pretty nice improvements to an already excellent image.

    Gordon
     

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