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Problems with bright lights in dark scenes (barco 708)

Discussion in 'Projectors, Screens & Video Processors' started by the jayman, Jan 11, 2003.

  1. the jayman

    the jayman
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    I have problem which is going to drive me crazy :mad:. In dark scenes, bright light sources are causing white horizontal lines. Lines are drawn only to the right side of the light source, starting from the light and ending to the border of the picture.

    I have already make some adjustments for this with contrast and brightness, those won't help. I have also tried two different RGBHV cabel, this won't help eather.

    I have heard that lousy (nonstable) power supply can cause this kind of behaviour, because drawed line won't be stabilized enough after bright light source. Could this be the explanation? Is there anything to do for this? Power supply mods?

    Projector is Barco data 708 with Skyworth 1050D progressive dvd player and using VGA output. Player outputs RGBHV signal and I have connected the player to the Barco with T connector for combining horizontal and vertical syncs. Barco has only RGBS input. Can this affect to those white lines?
     
  2. Charlie Whitehouse

    Charlie Whitehouse
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    My Barco Cine 7 suffers from an identical problem. According to Roland Brooks, many of the 700 series suffer from this too. Barco did produce a fix for it, but since these are no longer current models, the fix is no longer available from Barco. Last I heard, Roland was looking into the possibility of building the modified circuit himself, provided he could get the circuit diagram out of Barco. I am currently awaiting an update from him as to how this is proceeding. HTH... You are not alone... :(
     
  3. tonymott

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    Try shifting the image using horizontal phase control to the far left so the last bit of the image on the right is black...this is in the manual for my barco 650 and works for me.The raster is always bigger than the image.Ensure you do not go off the edge of the tube face with the image....Have you set the projector up using barco installation manual from scratch...well worth it.
     
  4. the jayman

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    Adjusting horizontal phase won't help in this case. I have already tried it. Setup for the projector is made "by the book".

    I think this is hardware problem, like Charlie suggested. If Roland could explain the fault little bit clearer, so I could find solution for this...
     
  5. the jayman

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    Here's one example picture with those white lines. Charlie, can you confirm that lines are similars with your Barco?
     

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  6. Charlie Whitehouse

    Charlie Whitehouse
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    It's not very easy to see in that example, but yes that is exactly what I get. The worst scene for this on my PJ is 'Go To Where People Are' (chapter 22?) from Unbreakable. Where Bruce Willis is wandering amongst all those people with the glass block walls down one side, you get loads of 'horizontal banding' across the screen exactly like yours.

    I initially suspected the scaler, but Roland got me to try plugging my laptop directly into the PJ with a Powerpoint presentation using a few white blocks against a very dark (NOT black) background, and the problem shows itself clearly.

    There is an expensive fix by replacing the whole end stage RGB amplifier, but Roland was looking to see if a cheaper modification was possible using a circuit diagram he was hoping to be able to get from Barco. Hopefully he will provide some more input here. :(
     
  7. Jeff

    Jeff
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    Luckily (for me) the 1209 doesn't have this problem.
     
  8. the jayman

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    I have to try Unbreakable, cause I have it (R1 though). Maybe I can get clearer example picture. One movie with lots of these problems is Dark City (which is used as good demo disc with many peoples). And I don't mean R2 UK disc (non-anamorphic letterbox), but anamorphic R2 (scandinavian release). 'The Others' R2 is other disc with problemous dark scenes.

    I've been told also that problem might be with tube amps, have you any idea how much it would cost to replace those? By the way, have you tried to adjust G2's?

    I'm going to test those lines with my Sony DVD player via S-video connection tomorrow. I have to make sure that problem isn't with connection type or my T sync construction. At least I didn't noticed those lines when I watched interlaced picture before buying progressive DVD player.
     
  9. Roland @ B4

    Roland @ B4
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    The "Streaky's" is problem with most CRT projectors Barco fixed it in later years with the BG808s and 1209s series. It will only be visable when the projector gets a low level background colour and a small very bright area. (odly it doen't show with a black backround) This is a projector design issue rather than a fault.

    You have to bear in mind that these projectors were designed for computor presentations. It is only the informed like us that have realised their potential for Home Cinema. It is only since we have started using these PJs for this rather fussy market place that issues like the streaky's have become apparent.

    There is a rather complicated fix to the amplifier board on the 700 series and I'm still working to get this resolved and produce it as a kit to fix the issue. It has taken an extreemly long time to get the specs and board design together. (Barco suggest changing the end stages at £1000). but we are getting closer.

    No amount of ajustment of G2's, brightness, contrast etc will fix the effect. it is a hardware issue.
     
  10. the jayman

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    Thanks Ronald for the reply.

    I have also heard that this could be more like feature than fault. It's still bothering me a lot and I have to say that 708 isn't as good as I suspected. Mainly cause of this problem.

    Do you know if streaking can be fixed by changing amplifier board from other 708 projector which has already been fixed? There must be projectors which are fixed with that expensive correction. How one can see if projector is already corrected? I'm just wondering if I can get spare parts from somewhere? :confused:

    Is the amplifier board same in 120V and 220V models? Can I switch those from U.S. models? Which models are compatibel with 708?

    I'm waiting also your fix. Please make this your first priority :D

    Here's also one picture from the Unbreakable. It's horrible :(
     

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  11. Roland @ B4

    Roland @ B4
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    Only the very last 708 range had the change done. I have seen two projectors through with it fitted as standard.
    It is a small sub board that was fitted to the RGB amplifier board that attaches to the end of the tube. Unfortuneatly you have to take the board off the tube to see if it present. There were several RGB boards for the 708 as it has about 4 different models.

    My goal is to get the kit to do all quite when I'm not sure just now.
     
  12. the jayman

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    Roland, is the official Barco's modification kit still avalable? Can it be ordered straigh from Barco?
     
  13. the jayman

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    Just pump up :)

    Roland,

    have you any idea about that last question?
     
  14. Roland @ B4

    Roland @ B4
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    The kit has been discontinued from Barco
     
  15. the jayman

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    Roland, any news about this kit?
     
  16. simon1967

    simon1967
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    Moi Jayman,

    can't help with your problem but it seems you have been pretty patient judging from the dates of your posts. I don't know if it will help but you could try some other guys - http://www.crtprojectors.co.uk/

    Henry and James are the men in question. They supplied and installed my Barco and are potty about CRT projectors. They dip into the forums occasionally but rarely post so I suggest phoning or e-mailing them. They really will bend over backwards to help if they can.

    Another thought is to phone Barco themselves and see if they can suggest vother routes. When I looked into buying a reconditioned Barco, they were very approachable even though they knew I wouldn't be buying a new machine.

    Good luck and believe it or not, I have been to Tampere. One of my work colleagues is from there but I guess you will not be pleased that he defected to Helsinki - I know how you two cities love to tease each other. :rotfl:

    Regards

    simon (Helsinki veteran) :smashin:
     
  17. Roland @ B4

    Roland @ B4
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    I have the board layout for this modification now but the guy who I have used for small board layout has now decided to move onto other things. Does anyone know of a company that will produce small run's on printed circuits.
     
  18. Mark Ward

    Mark Ward
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    I can't volunteer him as he's on holiday this week, but I know someone who could possibly do these for you. He's the guy I was going to get to do my Arcam SDI mod before I chickened out. He's a retired commercial amplifier manufacturer.

    I'll phone you a bit later,

    Mark.
     
  19. Kris

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    Was this problem fixed on the Cine-7 (2000/7)? Haven't seen it so much but sometimes on certain channels I see it on my CRT RPTV (Sony 42").

    //Kris
     
  20. Roland @ B4

    Roland @ B4
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    The cine 7 series will not be affected.
    (Charlie's machine is a special build and one of the very first off the line)
     
  21. Kris

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    God - Jesus - Roland Brooks!!

    Thanks for all your help here!!

    //Kris
     
  22. Roland @ B4

    Roland @ B4
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    I have now sent the one board (you need three RG&B) I had left off to a local company for them to cloan. I'll come back with a cost as soon as I have one.

    Send me an email if you would be interested.
    roland@b4projection.co.uk
     
  23. the jayman

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    Finnish Barco dealer doesn't know nothing about CRT's :) I've already adjusted my own projector after the official service, and noticed lot's of complaints :(

    I've also tried Curt Palme (if you know him), and he couldn't help me. If Roland can, it's enough for me.

    No probs, I think the main teasing is occurring during the ice hockey season. At least from the last season when Tappara (from Tampere) took the gold medals:D Best team from Helsinki was something like third or fourth...
     
  24. the jayman

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    And Roland, I'm definitely interested.

    Please sent update to this thread when you know more about it...
     
  25. Pipoplus

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    Hello,
    I am from the Netherlands and I have the same problem with my BD 701s and I know of others who experience the same prob.
    Roland; your solution wil be appreciated!! (I hope you have some good news for us)
     
  26. Roland @ B4

    Roland @ B4
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    First set of boards failed so modifications on way.
    I need to test here first obviously
     
  27. the jayman

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    Roland,

    Any updates?
     
  28. pekantol

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    The board what are you looking for is r762757s I think.
    If it helps you.
     
  29. Vince M

    Vince M
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    There comes a point where you are throwing good money after bad If a cost effective fix cannot be found.
    Depressing though It may be,It may make more sense to sell the 708 on and upgrade using the cash you may have allocated to fix.

    A downside of crt is that though they may be cost effective to buy,they can be expensive to fix-to the point in some cases where Its more cost effective to buy another.
     
  30. joflo

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    hello roland,

    maybe you can publish or send the mod so i can try to implement it and make a MOD , i have the R762559 module and i am bored. i like to mess with my pj . Anyhow i am thinking to upgrade to 8" but an extra exercise on 7" would not mind.

    for the ones with enough money and really bothered with the fault i might be able to help (pm)
     

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