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TV Trouble follow up, please advise

Discussion in 'Electronic Repair' started by [email protected], Mar 23, 2007.

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  1. Guest

    the original body of my post is copied below. To it i will add the
    following facts.....

    - to clear up the issue, the picture converges only from the top and
    the bottom, and the picture remains at the full horizontal length of
    the screen
    -The problem occurs after the TV has already been on for a variable
    length of time (+- 20 minits) and never occurs when you first turn it
    on (this may be explained by some type of expansion due to
    heating????)
    -the model number is: CF32E50 (Toshiba)
    -chassis number: TAC9516
    -manufactured apr. '96

    I am going to attempt to resolder the verticle IC. But first I have a
    couple questions I was hoping some of you would help me with.

    -How do I know where on the inside of the computer the verticle IC is?
    -Is it on a heat sink?
    -Which of the pins on the IC should I resolder, or should I just
    resolder them all?

    please advise, and thank you in advance for all of your help



    ---------------------------ORIGINAL POST-------------------
    I have a Tobisha TV. It is 32 inches. I do not know when it was
    made
    but I would have to say late 90's, maybe 98-99. It is your standard
    old TV, not one of the new fancy ones that everyone is buying.

    Here is the problem.....


    The image on the television constantly contracts. The sound is
    perfect. When you turn the TV on the picture is fine. After a
    certain amount of time, which is variable and (seemingly) random, the
    picture slowly condenses to the center of the screen. It would seem
    like someone is squeezing the picture from the top and the bottom
    simultaneously. The picture squuezes into a rectangular box in the
    center of the screen, about 6 inches on the side, while the rest of
    the tv remains black. There is no squeezing from the left or the
    right. Sometimes this picture will flutter between 3 inches wide to
    maybe 9 inches wide on the side. Sometimes while in this state the
    picture will spontaneously jump back to the full size and stay there
    for a couple of minutes, only to return inevitably to the condensed
    version.


    Upon smacking the top of the TV with my fist the picture returns to
    the full screen every time. If i only lightly smack it it will grow
    larger on the top and the bottom. So smacking fixes the problem
    temporarily.


    I would appreciate any and all input anybody has on this matter. I
    am
    determined to get to the bottom of the issue and would not mind
    attempting to fix the problem on my own. Please let me know if
    anyone
    can diagnose the problem and reccommend a possible solution.


    Thank you very much,


    Best Regards,


    Andrew Kotheimer
     

  2. The vertical circuit area of the board might actually be marked
    "vertical" or "vert"
    Do you know how to solder well and spot bad solder joints?
    Even if one or two pins seem bad, you should resolder them all.
    Then look with a magnifier to make sure you haven't accidentally bridged
    between any of the pins.
    Be sure to clean up any accidental solder drips and/or splashes.
     
  3. Charlie East

    Charlie East Guest

    Vert IC will be on heat sink. You may need a magnifier to see the bad
    solder. And it may be a component other than the IC,
    Charlie
     
  4. Guest

    Bad connection, maybe 2, nothing to do with convergence. Bad
    connection can be found by gently tapping points on pcb with a plastic
    tool with set on. But if youre not familar with the hazards and how to
    not fry on them, leave it alone.

    Semirandom resoldering is not a good approach.


    NT
     
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