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High vottage too high? ;)

Discussion in 'Electronic Repair' started by mm, Jan 2, 2007.

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  1. mm

    mm Guest

    I'm working on a Sony KV2080R 19" color, fairly old, but the question
    sort of relates to all tv's.

    It worked well except I heard a few cracks and saw a blue light coming
    from the back of the tv. It was a spark about 1 1/2" long from the
    flyback transformer to another part of that, shaped soemthing like a
    BIC lighter with square corners. Is that the tripler?

    As you can tell, I'm only an amateur, but I've had good results in the
    past 30 years with 3 or 4 tv's and one microwave oven by covering
    sparking areas with GE Silicone cement/sealant.

    This time, I put on a quarter inch coat (I don't think it will dry
    right if it is too thick), and let it dry 12-20 hours and then the
    spark moved somewhere else on the transformer. That happened two more
    times, with the spark moving each time, and then a third time the
    spark was at the base of a capacitor mounted to the pcb but next to
    the flyback. Coated that with GE silicone and then the spark was back
    on the flyback, real short, only an eighth of an inch, and at the
    surface of an earlier heavy coat of my silicone (I put a first coat of
    1/4 inch on, and since I'm still having trouble this time, I've been
    putting on a second quarter inch coat.)

    Is this not uncommon? or
    Is the high voltage too high? or
    Do SONYs have higher voltage than the other tvs I've done this with?
    or
    Do you disapprove of the whole technique? :) or
    Why is this happening this time when it never did before?


    I didnt' really wait to see how many times it would spark when this
    all started, because I thought it was bad for the tv to be sparking at
    all, ??, so I would turn it off, but some later times it was hard to
    find the spark, so I would leave the tv on, and I've noticed that
    lately it only sparks about 4 times, every 10 seconds, and then it
    seems to stop. This last time, it only sparks 3 times and then stops
    for at least 10 minutes (when I turned the tv off each time) and
    wouldn't start again if I only left the tv off for an hour or two. I
    think after 12 or 24 hours it will spark again, 3 times, and stop.

    I'm keeping the tv for myself, so maybe I should just live with this??

    From early on I noticed that either the spark doesn't affect the
    picture, or it makes one white horizontal line across the picture for
    a split second.

    I have half a caulking tube of of GE sealant, and I can keep putting
    the stuff on until I've covered everything within 2 inches, but I
    thought I should ask you guys before I went much further.




    If you are inclined to email me
    for some reason, remove NOPSAM :)
     
  2. Charlie East

    Charlie East Guest

    Replace the flyback, Probably has a crack
     
  3. b

    b Guest

    that object could be a fusible resistor.
    In any case, if you mean to keep that tv, don't mess about wasting your
    time with this botch repair. Just buy a new transformer before you end
    up damaging the nearby circuitry- ICs dont tend to like being zapped by
    20,000 volts ;-). check the reference in the www.hrdiemen.es website.
    -B.
     
  4. James Sweet

    James Sweet Guest


    Figure out exactly where the crack is that the spark is coming from and
    caulk over that. If all else fails, replace the flyback but usually you
    can fix arcing problems like that.
     
  5. mm

    mm Guest

    Thanks. That's what I wanted to hear, if I was the only person doing
    things this way.

    Believe me, I looked each time, where the spark was at first and each
    time it moved, and I couldn't see either a crack or a pinpoint hole or
    even a mark. That's why I started to think the high voltage was
    higher than normal.

    (A couple of the places where sparks started or ended were at a
    boundary of some sort, like the bottom or where the metal core met the
    rubber cover. But in the other 4 cases, I could find no crack. The
    spark moved every time!)

    To Charlie and B:
    Thanks for replying but it's really not worth buying a flyback. It's
    not high def, it's going to be obsolete in 2 years, and I have lots of
    tvs. This will just be a spare.

    The goal of my question was to understand this, only secondarily to
    fix the tv.


    If you are inclined to email me
    for some reason, remove NOPSAM :)
     
  6. Guest

    Its necessary to remove every trace of carbon before applying
    insulator, otherwise it wont work. Practically, it will die quickly,
    bin it.


    NT
     
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