Alignment/Raster Question - Too Easy!???

Discussion in 'Projectors, Screens & Video Processors' started by Lux In Umbra, Sep 21, 2004.

  1. Lux In Umbra

    Lux In Umbra
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    Just a quick (easy) question:

    Given a straight-forward setup (pj centered, right height, correct angle, right distance, etc)...

    Should the RED and BLUE lenses/tubes be at the same angle wrt the green lens/tube?*

    At the moment I've got a "professionally set-up" projector with the BLUE tube/lens at a different angle wrt the RED-GREEN angle.... and the BLUE raster shift (in convergence) pretty much at 100%.

    Is this a big NO NO? And will it actually do any harm (eg: stressing components)?

    (The blue raster is visibly not the same offset from the tube edges as the red, as well, btw)


    Thanks for any suggestions/advice/etc...



    *IE: If the RED-GREEN angle is, say 20 degrees, should the BLUE-GREEN angle be ~20 degrees as well??? At the moment you can see the difference in angle easily just by looking at the front of the projector.
     
  2. Mr Cinema

    Mr Cinema
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    Doesn't sound right. Seems like you need to start from scratch. What is the projector?
    My knowledge currently only extends to Barcos.

    Use the install menu and centre the rasters on the tube, then you can adjust the lens' using the cross hairs. Sound like this has been done electronicaly rather than physically moving the Blue to match the green. Bad idea.

    But as I say, this relates to Barcos. Your PJ may have a different set up.
     
  3. Lux In Umbra

    Lux In Umbra
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    Silly me to blame the professional, perhaps!

    I went and did the full re-install, and guess what...

    The tubes are now almost exactly at the angles they were before, and I've got the rasters certainly not centered!

    Why?

    Because to get the rasters centered on the tubes, the electronic adjustments end up at ~100!

    So, I've decided - bugger that ... the rasters dont come too close to the edge, they just are closer to one side than the other, and I think its much more likely that centering them with settings at the limit is worse than not using a little phosphor at the edge of one side of the tubes.

    {And, yes - before you ask, the projector is centered!}

    So, unless I hear to the contrary, thats how I'll probably leave it.

    (BTW: Yes, its a Barco 708, and it is a breeze to install ... people who say CRTs are so hard obviously aren't used to installing software/OSs !!!)
     
  4. Roland @ B4

    Roland @ B4
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    Lux ignore the cross hair it is fine for brand new projectors just out of the factory but things will have changes since then. Set your rasters back to 50% for red and blue . then look at the underside of the focus shift board you will see two blue pots with BRASS tops (the only ones) use these to centre the raster.
     
  5. Lux In Umbra

    Lux In Umbra
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    Aha! Thank you, Roland! (BTW: Which is the focus shift board? I am new to this!!! I hope I dont have to dig around too much... dont want to kick off a chain reaction of problems!)
     
  6. Lux In Umbra

    Lux In Umbra
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    I really dont want to BUMP anything while doing this...
     
  7. cosmic023

    cosmic023
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  8. Lux In Umbra

    Lux In Umbra
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    Legend!

    Now I just need to align the pictures with what I actually see when I open up and dig around. NB: I was not expecting them to be so tiny! (I assume they are the same on the 708 as the one in the picture ?800? ... oh, and that its safe to play around in that region during normal operation...)

    Thanks!
     
  9. Lux In Umbra

    Lux In Umbra
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    Well, I've now done the adjustments to R&B raster position with the tiny screws. (Boy do they take a lot of turns to adjust ... I proceeded with caution turning just a small fraction of a revolution at first - with no change in position whatsoever. In the end it took quite a few turns to move them!) {NB: I also found out that they are actually marked, as is the focus board ... so dont I look ignorant!}

    Is there any other way than with the digital controls to move the green raster? (Its a little bit off centre).

    The good news? Now the R&B tubes are pretty much the same angle to the green! Looks much suitable!

    Thanks!
     

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