Help! played around with the pots on my 50H81 tosh

Discussion in 'Archived Threads 2001-2004' started by Peter Conn, Jan 22, 2002.

  1. Peter Conn

    Peter Conn Auditioning

    Joined:
    Dec 30, 2001
    Messages:
    8
    Likes Received:
    0
    Trophy Points:
    0
    I think I entered the forbidden land, and tweaked the color adjustment pots under the cover on my Tosh 50H81. Is there an idiots guide to getting the Red, Green Blue back to what they should be. tried following Avia, but once off into the more techy stuff find there is not enough explanation on how too. Any help in the right direction would be appreciated.
    [​IMG]
     
  2. Jay Mitchosky

    Jay Mitchosky Producer

    Joined:
    Sep 6, 1998
    Messages:
    3,729
    Likes Received:
    0
    Trophy Points:
    0
    Peter

    Which pots did you touch - Focus VR or Screen VR? If you played with the Screen pots I have some incredibly bad news for you: you need to call a technician with a grayscale measurement device (preferably a color analyzer) to properly set them again. You should never play with those controls unless you have the proper equipment to get them back again.

    If you adjust the Focus VR pots things are OK - you'll just need to remove the screen and fine tune the adjustment. These adjust the focus of the beam spot on the CRT lens itself (not on the screen). Bring up a crosshatch pattern and look directly into each lens (wearing a pair of sunglasses helps - I swear). Adjust the respective FOCUS pots until you see the sharpest lines. You'll be able to tell by looking at the edges - they'll look like teeth from a comb. The sharpest point also coincides with the lowest light output. If you're more sensitive to that use it as your barometer instead. I like using a full field image and adjust until all the scan lines are cleanly resolved.
     
  3. Peter Conn

    Peter Conn Auditioning

    Joined:
    Dec 30, 2001
    Messages:
    8
    Likes Received:
    0
    Trophy Points:
    0
    I messed with all of em [​IMG] (ignorance is bliss), the focus stuff was easy, but the top ones [​IMG] I guessed as much, I believe the 4 year BestBuy allows, 1 maintenance per year time to call. in the meantime is there a rule of thumb to follow to get somewhere near what it should be. Thanks.
     
  4. Jay Mitchosky

    Jay Mitchosky Producer

    Joined:
    Sep 6, 1998
    Messages:
    3,729
    Likes Received:
    0
    Trophy Points:
    0
     
  5. Gregg Loewen

    Gregg Loewen Video Standards Instructor, THX Ltd.
    Insider

    Joined:
    Nov 9, 1999
    Messages:
    6,374
    Likes Received:
    32
    Trophy Points:
    6,610
    Location:
    New England
    Real Name:
    Gregg Loewen
    HI!

    Here we go...do so at your own risk...

    find a 4 pattern plunge chapter on Video Essentials.

    Adjust the trim pots to find a "pretty even" pattern of grey through out the different IREs.

    Try to keep the trim pots somewhat centered.

    After youve done this verify that each of the guns has approx. the same width, via seperating them in the convergence menu (service level).

    I have a very strong suspection that this is what many techs do to acheive "adequate" grey scale without using a color analyzer. And they leave out measuring the line width too.

    Best of luck and may the force be with you!!

    Gregg
     
  6. JohnnyG

    JohnnyG Screenwriter

    Joined:
    Dec 18, 2000
    Messages:
    1,522
    Likes Received:
    0
    Trophy Points:
    0
    Let me add my 2 cents worth to Gregg's instructions. Take off the screen, select a video Input with nothing connected to it and look into the green (center) lens. Adjust the green Screen trimpot until you can see a raster on the face of the CRT and then back it off very gently until the raster just vanishes. Now put the screen back on and follow Gregg's instructions, but don't touch green again.
     
  7. Peter Conn

    Peter Conn Auditioning

    Joined:
    Dec 30, 2001
    Messages:
    8
    Likes Received:
    0
    Trophy Points:
    0
    Thanks Guys, I have been doing it by eye, got reasonable results, The convergence stuff went well, notice a marked cripness to the PBS HDTV signel. It's more the balance of color that seems hard to get right. I notice it varies a lot from Cable to HDTV and DVD. Purples tend to be a little blueish, browns -- greyish (only in low light scenes) and dark scenes a touch greeny. I have myself down for the ISF coming to VA soon I hope...

    :b Any further tips are welcome...
     

Share This Page