HS10 Blue CRT Focus

Discussion in 'Archived Threads 2001-2004' started by Lanny Hoff, Jun 19, 2001.

  1. Lanny Hoff

    Lanny Hoff Stunt Coordinator

    Joined:
    Dec 20, 2000
    Messages:
    59
    Likes Received:
    0
    Trophy Points:
    0
    I've tried to focus my HS10 as well as possible, but the blue crt, true to form, is damned hard to get very focused. I've done the electrostatic focus with the PICTURE control all the way down, and that seemed like the clear winner way to do it, but I wonder if I'm wasting my time trying to get the blue CRT anywhere near as focused as the red and green?
    Has anybody out there acheived total blue gun nirvana, and what did it take? I tried focusing the CRT's mechanically with the paper on the screen trick, but old blue is still a little fuzzy.
    I guess I would appreciate somebody to say "it's not possible to get the blue as focused as the other ones, so relax."
    Anybody who knows willing to say that?
     
  2. TerryBlauser

    TerryBlauser Auditioning

    Joined:
    Apr 21, 2000
    Messages:
    12
    Likes Received:
    0
    Trophy Points:
    0
    "It's not possible to get the blue as focused as the other ones so relax"
    There do you feel better I hope?
    Everything I've seen in the forums and in my experience says this is so. Make a good attempt and then quit. You can't get past the deminishing returns rule so enjoy a very good display.
    Mine just survived a 200 mile move from Corpus Christi to Houston so now it's time to take the glare inducer off and add the black liner back in.
    PS is the plural of forum fora?
     
  3. Lanny Hoff

    Lanny Hoff Stunt Coordinator

    Joined:
    Dec 20, 2000
    Messages:
    59
    Likes Received:
    0
    Trophy Points:
    0
    Terry,
    Thanks for your response. I believe you mean it, and you're not just saying it to make me feel better.
    The display does look good, and I am pretty happy with it, so maybe I'll just watch some films now, eh?
    Glad to hear your set made the trek. It's a little nerve-wracking having these expensive monsters bounce around the back of a truck, isn't it?
    Lanny
     
  4. TimG

    TimG Second Unit

    Joined:
    Oct 5, 1999
    Messages:
    361
    Likes Received:
    0
    Trophy Points:
    0
    The blue being slightly out of focus has something to do with geting the right white level. I don't know the specifics.
    Tim
     
  5. Guy Kuo

    Guy Kuo Supporting Actor

    Joined:
    Mar 6, 1999
    Messages:
    581
    Likes Received:
    0
    Trophy Points:
    0
    Basically, the blue CRT has difficulty keeping up with generating sufficient light output at the upper end of the IRE scale. That is, the brightest portions of images. In order to keep things in balance it is necesary to do one of two things.
    a. Limit maximum light output to levels which can be achieved with a fully focused blue gun. This works but ends up with a maximum light output which is perhaps half as much as possible in option b.
    b. Defocus the blue gun slightly to increase blue gun light output. This blurs blue slightly, but since the human eye is quite poor at detecting details in blue anyway, the effect on image sharpness is minimal compared to the large increase in possible light output from the display.
    If you adjust blue gun beam focus in an RPTV or FPTV which is CRT based, you WILL alter its grayscale tracking as well as the focus. On direct view CRT's, the blue gun isn't has hard put to keep up with the other two guns so defocusing blue isn't needed there to maintain good grayscale tracking.
    ------------------
    Guy Kuo
    www.ovationsw.com
    Ovation Software, the Home of AVIA DVD
     

Share This Page