Toshiba 50" vertical/horizontal hold problem.

Discussion in 'Displays' started by JeffWill, Sep 12, 2005.

  1. JeffWill

    JeffWill Auditioning

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    Need Advice on this one.....

    Out of no where the picture just starting "scrolling" sideways and I can't seem to figure out how to stop it.

    Thanks
     
  2. Allan Jayne

    Allan Jayne Cinematographer

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    Every CRT TV has vertical hold and horizontal hold controls somewhere, usually in back. You may or may not be able to get to these controls without removing the back cover.

    Some TV's allow limited vertical and horizontal hold using service menu entries. The physical controls in back will shift the effective range or scale of the service menu controls if any.

    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  3. JeffWill

    JeffWill Auditioning

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    Now....out of no where the TV stopped "spinning" horizontally and the picture is fine...

    Does this sound like possible trouble for the TV or did it just magically "sync" itself back up???
     
  4. JeffWill

    JeffWill Auditioning

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    Didn't last.....picture "srolling" non-stop again sideways...
    I opened the back up but I don't see any "buttons" or controls that I can "turn"...IS there some way into the service aspects of the TV through the remote??
     
  5. JeffWill

    JeffWill Auditioning

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    c'mon people....51 people looked at this thread and no one here has any help for me??
     
  6. Allan Jayne

    Allan Jayne Cinematographer

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    >>> c'mon people....51 people looked at this thread and no one here has any help for me??

    We're all stumped. That's the main reason why questions on this forum go unanswered.

    Nowadays there are very few if any independent experts who are available to quickly pinpoint what is wrong with a TV or an appliance or an automobile or whatever. Therefore so many of these things are thrown out and new ones bought rather than try to find out what is wrong whcih can be costly and time consuming.

    When something suddenly goes wrong with a TV chances are a part on a circuit board has gone bad. It is rare to find a TV repair shop where someone knows how to troubleshoot circuit boards and replace individual parts so at best the entire board is removed and replaced.
     
  7. Dave Kingma

    Dave Kingma Auditioning

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    Well you want some help. I have a 36" Mits tube set and I did take the back off to find controls. I had very bad over scan, Hor. and Vert. I did find the controls (pots) on the board for both. Very small lettering on board by the pots. Did a perfect adjustment. I didn't see any to do with HOLD. I think that is a thing of the past. Board is small, lots of SMD (surface mounted device). I would think board has to be replaced - but don't know.

    Anybody remember HEATH KIT? I built there color TV - 35 to 40 years ago. Tube set, best TV on the market at the time. You could of course repair and converge the three color guns your self. I was a HEATH KIT freak, loved building there products.
     
  8. rob-h

    rob-h Second Unit

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    Becareful playing with the controls with it plugged in. Very high voltage.

    If you trun the TV off for a long while does it stop scrolling when you turn it back on then after a while start? That would indicate that it's tempeture related. Most likely a bad cap in the hold circuit. Should be easy to identify and replace. If you dont have experiance at this, its better to let a pro do it.
     
  9. DavidES

    DavidES Stunt Coordinator

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    Without knowing what type/brand/model tv you have, sounds like the horizontal oscillator is starting to miss it's sync pulse from the sync separator. Which direction does it scroll?

    Though the way TV circuits are for standard CRTS now, most of all that is contained in what we call a video 'jungle chip' and contains countdown circuits. Too much to explain here.

    Is it still under warranty if so you did save the paper work, right?

    Call a reputable tech in.

    Unless you know how to fix tvs or electronics which it doesn't sound like you do, I really wouldn't recommend your hands inside the back of the tv. Button it up and call that tech.
     
  10. JeffWill

    JeffWill Auditioning

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    okay....sounds like I need good technical help...I wnet on the Toshiba website and looked up "authorized dealers" and found one close by. Guess I have to them in to fix. Thanks for the advice
     
  11. John Whittle

    John Whittle Stunt Coordinator

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    A wise decision. Many (though not all) modern televisions sets do not have horizontal controls because they have a chip that "counts down" from the vertical interval and sets the rough horizontal frequency and then a phase lock loop will lock onto the horiztonal. If you're picture is scrolls sideways (and not just scrambled like in the good olden tube days) then the picture is stable and it might be something in the deflection circuits.

    Only someone with the knowledge of that set will be able to pinpoint the problem since there are now so many variations on the standard design of the old tube/descrete solid state sets.

    John
     

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