Sears, my Mits and overscan! Ahhhh!!!!

Discussion in 'Archived Threads 2001-2004' started by Timon Russo, Oct 6, 2002.

  1. Timon Russo

    Timon Russo Stunt Coordinator

    Joined:
    May 10, 2000
    Messages:
    213
    Likes Received:
    0
    My 65807 is still under its two year MA from Sears, so I decided I would have them come out and help me reduce my overscan, and fix some convergence probs on the left and right side of the screen.

    Firstly, I borrowed AVIA, and have the service menu codes, but was afraid to go it alone. And secondly, I cannot afford a professional ISF calibration right now.

    So after telling the guy about overscan, and how especially on the left side, things were getting chopped off, I showed him the AVIA grid and a printout with some codes. He went into the service menus, and fiddled around for a while.

    He reduced it as much as he could (which I believe, as I was watching him), but now the image is bowed on the left and especially right side of the screen. He said there wasn't much he could do, and thats what was going to happen when you reduce overscan that much (its at 5% on each side).

    So, now the image is slightly skewed, especially the lower right part of the screen. Also, I noticed something else I really don't like. Using the STRETCH mode, I can now see some weird effect on the left and right portions of the screen, almost as though its somewhere between stretched and not stretched, and the area affected seems to match exactly the amount of image reclaimed by reducing overscan! In other words, I've got more picture, but the STRETCH algorithm doesn't seem to handle this new area well at all.

    Can I fix this? Can I also fix the bowing problem? Is it possible to have 5% overscan AND perfect geometry? Please help!!!!!!

    Thank.
     
  2. Gregg Loewen

    Gregg Loewen Video Standards Instructor, THX Ltd.
    Insider

    Joined:
    Nov 9, 1999
    Messages:
    6,373
    Likes Received:
    32
    Location:
    New England
    Real Name:
    Gregg Loewen
    5 % is what I set overscan to on Mits RPTVs. After you do this, you then need to use the green convergence grid to straigthen out the lines. Then do the red and blue guns to convergence the image on to the green. If found that if you try to reduce overscan further on the MIts line you cant get the corners properly converged.

    Hi def is seperate from 480P mode too. So each has to be done seperately.

    Best of luck!

    Gregg
     
  3. Timon Russo

    Timon Russo Stunt Coordinator

    Joined:
    May 10, 2000
    Messages:
    213
    Likes Received:
    0
    Gregg -

    Thanks a bunch. I got in there and did the green grid like you said and I must say my geometry problems are licked. Thanks.

    However, I still wonder if there is another setting that pertains to the stretch mode, as I continue to see that weird effect on the left and right sides of the screen when using that mode. I can only describe it as a ripple effect along vertical lines on the left 1" or so of the screen. Less on the right, but as I said, its proportional to the overscan adjustments we made.

    Its as though the stretch mode isn't applied to the new area we are seeing after reducing overscan. Or its applied in a weird way.

    The wife doesn't really notice it. It bothers me pretty bad.


    Any thoughts? Anyone?
     
  4. John Royster

    John Royster Screenwriter

    Joined:
    Oct 14, 2001
    Messages:
    1,088
    Likes Received:
    0
    how does standard mode look?

    Can you bring up a AVIA geometry patter and stretch it? I'm still thinking you have a little more geometry work to do.
     
  5. Mark Amayao

    Mark Amayao Stunt Coordinator

    Joined:
    Dec 13, 2001
    Messages:
    156
    Likes Received:
    0
    when reducing overscan on my set (pt47wx51) i made sure that overall geometry on the whole screen was correct from the outside in, towards the center .... though you can eyeball this (and come close) im sure some sort of template or grid can be used for accuracy. See if you can have the service tech adjust grayscale for you after you do this.
     
  6. Timon Russo

    Timon Russo Stunt Coordinator

    Joined:
    May 10, 2000
    Messages:
    213
    Likes Received:
    0
    Only stretch mode is affected by this anomoly. I put up a moving AVIA image and watched it as it went from the center to the left side of the screen. First it was natural, then it became increasingly stretched as it went to the left side of the screen, then for the last inch or so on the far left, it snapped back to totally unstretched. So during camera pans, which were always obvious using stretch mode, its even MORE obvious now, as it starts out (on the left, lets say) unstretched, suddenly snaps to very stretched, then gradually evens out is it pans to the center.

    All the grids I put up look perfectly symetrical. Can this still be a geometry issue? It doesn't look that way to me, but I might be using the wrong terms.

    As I said, there is also a strange ripple effect in this portion of the screen. Even when there is no camera movement, you can tell something is wrong there, and not just because of the geometry. I'm not sure if I can capture it on my digital camera, but I will try.

    Thanks for all the info so far. This has been very helpful. You guys really seem to know your stuff.
     
  7. Timon Russo

    Timon Russo Stunt Coordinator

    Joined:
    May 10, 2000
    Messages:
    213
    Likes Received:
    0
    Unless anyone has any other ideas, I'm going to call Mits today and ask them.

    Would it be useful to purchase the service manual, I wonder?

    Bottom line is, I don't know what the Sears guy did in those menus, because I wasn't watching the whole time. And even if I was, I don't know what all that stuff means.

    I might try to go in and put my overscan back to see if the problem goes away, but I'm not even sure I know how to do that.
     
  8. Timon Russo

    Timon Russo Stunt Coordinator

    Joined:
    May 10, 2000
    Messages:
    213
    Likes Received:
    0
    For the record, I cranked overscan back UP a little more and the problem went away. I learned the service menus by jumping in blindly. Very nerve wracking.
     

Share This Page