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How fix lines on CRT from signal lead ?

Discussion in 'Electronic Repair' started by Jon D, Aug 24, 2006.

  1. lsmartino

    lsmartino Guest

    CBFalconer ha escrito:
    Please, reread the post. I said "...A bad flyback will not worsen or
    improve by "wiggling" the VGA CABLE OF THE MONITOR..." Did you noticed
    the "VGA CABLE" part of the sentence?

    And the Flyback isn´t even in the same PCB as the VGA cable is. So
    there is no way that disturbing the VGA cable will cause any physical
    displacement of the flyback.
     
  2. Rod Speed

    Rod Speed Guest

    Wrong again, particularly when you deliberately
    restrain the cable and wiggle/flex the video card end.
     
  3. johns

    johns Guest

    That pulls the wire .. which pulls the other end connector
    .... which pulls the crt card .. which wiggles the crt ..
    which wiggles the main board ... you can't test that
    way. It will fool you a million times.

    johns
     
  4. Rod Speed

    Rod Speed Guest

    No it doesnt if you restrain the cable.
    No it doesnt if you restrain the cable.
    No it doesnt if you restrain the cable.
    No it doesnt if you restrain the cable.
    No it doesnt if you restrain the cable.
    Corse you can.
    Only those that are very easily fooled and cant
    even manage to restrain the cable while flexing
    the video card end.
     

  5. Agreed... Sounds like a bad VGA cable or possibly the connector on the
    video card. I don't even know why there is even any debate about this.
    Replace the VGA cable first. If the problem still exsists afterwards it is
    elsewhere. The guy talking about the flyback is just trying to be a troll
    and start a huge arguement over nothing.
     
  6. Guest

    The following extracted from:-

    http://en.wikipedia.org/wiki/Internet_troll#Attention-seeking_trolls

    Attention-seeking trolls

    This class of trolls seeks to incite as many responses as possible and
    to absorb a disproportionate share of the collective attention span.

    * Messages containing a deliberate flaw or error: "I think 2001: A
    Space Odyssey is Roman Polanski's best film." Or "Federico Fellini is
    the Greatest Living American Director"

    *Asking for help with an implausible task or problem: "How do I season
    my Crock Pot? I don't want everything I cook in it to taste the same."

    *Intentionally naive questions: "Can I cook pasta in Evian instead of
    water?"

    *Intentionally posting an outrageous argument, deliberately constructed
    around a fundamental but obfuscated flaw or error. Often the poster
    will become defensive when the argument is refuted, and may continue
    the thread through the use of further flawed arguments; this is
    referred to as "feeding" the troll.
     
  7. Guest

    If you dont think wiggling a thick fat video cable can wiggle the
    plastic base that the main board sits on, and thus the main board, then
    either you havent repaired too many monitors, or youre a moron. Almost
    certainly both.

    NT
     
  8. Rod Speed

    Rod Speed Guest

    wrote
    Never ever could bullshit its way out of a wet paper bag.
    Any 2 year old could leave that for dead.

    Get one to help you before posting again, if anyone is
    actually stupid enough to let you anywhere near one.
     
  9. Rod Speed

    Rod Speed Guest

    wrote
    All completely irrelevant to whether what he was doing
    had anything what so ever to do with attention seeking.

    He may well be just another rather irrational individual.
     
  10. kony

    kony Guest


    It depends entirely on how well that cable is fixed
    internally. Some certainly would but quite a few wouldn't.
    So yes it's possible but not necessary true.
     
  11. Eric

    Eric Guest

    Hi Jon

    As electronic equipment gets older, the Electrolytics begin to fail, the ESR
    begins to rise.
    A failing Electrolytic would cause top fold over.
    If you look at a typical vertical drive circuit, Electrolytics near the
    circuit B+ to ground would cause top fold over,
    While Electrolytics near ground potential to ground would cause bottom
    linearity problems.



    My 17 inch CRT sometimes gets ...

    light-colored horizontal lines
    a couple of inches above the bottom of the screen
    usually just one or two of these
    the picture size too *sometimes* seems to get a tiny bit smaller
    when these lines are present.

    I have tracked this down to the signal lead going from PC to monitor.

    This d*mn lead seems quite sensitive because slight kinks and bends
    in the lead can create this effect. So can gently moving the plug as
    it goes into the video card. Why can't they design a better lead
    than this? It is already the most inflexible lead on my whole
    system!

    MY QUESTION IS ... is this lead usually as sensitive as this or is it
    related to the design of my particular monitor and PC interface.

    Can I do anything to improve the situation? I have lowered the
    screen refresh rate a bit but that doesn't seem to have help.

    Is there a "magic bullet" like something to clip onto the leqad or
    some screening.

    Changing the lead means some tricky messing around inside the monitor
    to terminate the leads it in the screened cage sitting on the cathode
    parts of the CRT itself.

    Any ideas?

    Jon


    [Please don't say buy a secondhand 17inch monitor for next to nothing
    because cleaning it and dusting out its internals to sharpen up the
    image and all that stuff takes time, and so does fetching a checking
    over monitors which turn out to be crap.]
     
  12. Guest

    a novel explanation.

    Lytics are always suspects, but I wouldnt give them too hard a time.
    All but one of the lytics on my 1930s radio are still fine.


    NT
     
  13. t.hoehler

    t.hoehler Guest

    My bench service on home entertainment goods shows an awful lot of dried up
    lytics, and bad solder joints. With rohs, I suspect the latter will become
    even more problematic.
    regards,
    tom
     
  14. Jon D

    Jon D Guest


    I am the OP.

    Guess you haven't read this thread earlier this year in
    sci.electronics.components

    http://tinyurl.com/jftyr
    "Any value in cleaning inside old monitor?"

    Many were skeptical like you. But the most convincing answers came from
    those who knew there was a value in doing this and I think they were the
    majority.


    EXTRACTS ...

    keeping components hotter than they would be if running in
    "free air" conditions.

    Not only does it have the chance of getting onto circuitry, it also
    changes the capacitance of the tube wall, changing the circuit for the
    CRT drive elements as well.


    The collection of dust, and much of that moistened at
    some point makes for a leaky anode supply and feed wire at the very
    least. That makes for poor or shifted focus settings, and other
    problems that less than your average video afficianado won't notice.

    Most folks rarely notice their focus shifting as well. One has to be
    video oriented to notice such things.

    Just to back the pro cleaning side, when I made my living from servicing
    monitors (and before that TVs) every once in a while I'd get one on the
    bench with the safety shutdown tripping because of a buildup of crap
    around the anode connector or other HV parts, but then I've also had
    nearly as many repairs in that people had damaged cleaning the inside
    when they didn't know what they were doing!
     
  15. kony

    kony Guest

    Nope, they did what most do, made random theories about what
    hypothetical advantage there might be, without any real
    evidence to support the theories. Let's suppose it did help
    a particular monitor, is that then evidence it is going to
    help most of them? No.

    Further we'd first need to know how old the monitor is (is
    it even worthwhile), how much crud accumulation there was,
    and a measured deviation from appropriate operational
    values. Of course it's not good to let parts overheat, or
    conduct along unintended paths... but what remains is
    actually having that happen. A monitor so poorly designed
    that it can't stand a little bit of dust may not be worth
    the effort, and one buried in dust might only be a sign of
    the real problem- the room needs better air cleaning
    equipment, instead of individually cleaning out every part
    over and over again.



    What good does it do to only provide "extracts" that support
    your biased opinion? Here's one you left out:

    On 3 Apr 2006, <Sam Goldwasser > wrote:

    If you're obsessive-compulsive and have nothing better to
    do, by all
    means clean the insides of your CRT equipment. But it's
    probably more
    likely that something will get messed accidentally, than any
    significant
    improvement in either performance or life span.


    The high voltage area of modern CRT equipment is generally
    enclosed and
    or sealed with HV grease or adhesive. It's not like old
    all-tube-type
    TVs where everything collected an inch of dust if you turned
    your back. :)


    Yes, dust does collect. And yes in principle that may
    affect something
    eventually. But if there are no symptoms, leave it alone.
     
  16. Jon D

    Jon D Guest



    I did what that thread suggested and I got a pleasant surprise in the
    improved focus.

    Maybe my monitor is shite.

    Maybe my room is shite.

    But that's my monitor and that's my room. And that what I have to
    deal with. A good de-dusting works nicely.


    I am glad to see you went to the thread and look through it. Well
    done.

    OTOH my extracts were for those folks who are sort of 50:50 undecided
    about checking that thread out. So I posted a random selection of
    extracts to show its relevance in the hope that the 50:50 readers
    would go and look.

    Hey! I did write, "Many were skeptical".
     
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