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television goes again by hitting the top of it?

Discussion in 'Electronic Repair' started by blanking, May 25, 2007.

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  1. blanking

    blanking Guest

    Hi there, I have a 12 year old sony tv that just suddenly started having
    problems, first sign of trouble was that when you turned it on no picture
    would come up, that includes osd, and then after about 10 seconds it would
    automatically shut down to standby mode again, no matter how many times I
    tried it just kept doing this until that is I gave the top of the tv a whack
    at which point all was fine again for sometime but then most of the picture
    would disappear and there would just be flickering strips of picture near
    the top of the screen and then if I did not give it some more whacks it
    would turn off again. Any ideas as to what this could be, could it be as
    simple as dust or is this the last dying gasps of the cathode ray tube, why
    would a whack help the tube to go again?
     
  2. The picture tube is likely fine, this is a problem far removed from it.

    Something is making bad contact, either a connector that is no longer
    making contact all times, or a bad solder joint.

    Michael
     
  3. Jamie

    Jamie Guest

    It has a Whack detector security option you turned on?
     

  4. If it does, you better stay away from it.


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
  5. Meat Plow

    Meat Plow Guest

    Bad solder joints. Take it to a tech.
    --
    #1 Offishul Ruiner of Usenet, March 2007
    #1 Usenet Asshole, March 2007
    #1 Bartlo Pset, March 13-24 2007
    #10 Most hated Usenetizen of all time
    #8 AUK Hate Machine Cog
    Pierre Salinger Memorial Hook, Line & Sinker, June 2004
    COOSN-266-06-25794
     
  6. JANA

    JANA Guest

    Probably a bad solder connection on the circuit board, or a component that
    is going mechanically intermittent. Take the set to a service centre, and
    get it properly fixed.

    --

    JANA
    _____


    Hi there, I have a 12 year old sony tv that just suddenly started having
    problems, first sign of trouble was that when you turned it on no picture
    would come up, that includes osd, and then after about 10 seconds it would
    automatically shut down to standby mode again, no matter how many times I
    tried it just kept doing this until that is I gave the top of the tv a whack
    at which point all was fine again for sometime but then most of the picture
    would disappear and there would just be flickering strips of picture near
    the top of the screen and then if I did not give it some more whacks it
    would turn off again. Any ideas as to what this could be, could it be as
    simple as dust or is this the last dying gasps of the cathode ray tube, why
    would a whack help the tube to go again?
     
  7. blanking

    blanking Guest

    Thanks but I want to give it a go myself, for 2 reasons, the cost of
    servicing compared to buying a new similar tv and I am reasonably handy
    myself with although limited electronic knowledge. I know there can be
    dangerous voltages left in the capacitors after turn off so I presume if I
    short the power plug phase and neutral pins to the earth pin I will
    discharge any voltage in the caps. The fact that it responds to a tap on the
    top of the tv makes me think it is probably not in the circuit board, it has
    settled down at the moment but the next time it goes haywire I will trying
    tapping different parts of the tv and see if i can narrow things down a
    little there before opening it up. Is it possible for dust to cause this
    sort of problem or are there no conductive parts exposed to the dust?
     
  8. James Sweet

    James Sweet Guest

    It's cracked solder joints on one of the boards, take it somewhere to have
    the problem fixed. Stop using it *now* and certainly stop whacking it, quite
    a few TV failures start out as solder joints then much more severe damage
    occurs because people continue to use the things.
     
  9. blanking

    blanking Guest

    Thanks, leaving solder joints out for the moment where am I best to look for
    this, I will trying
    tapping different parts of the tv and see if i can narrow things down a
    little there before opening it up so you may want to wait till i have done
    this before you answer my question, thanks.
     
  10. blanking

    blanking Guest

    I will look into safety measures before working on the inside of the tv and
    i certainly will not try working on it with the power turned on.
     
  11. James Sweet

    James Sweet Guest


    It's on one of the boards, guarranteed. When you tap on the top, the
    vibration passes through the entire chassis. Pull the back cover off and
    poke around with an insulated stick, a wood dowel works pretty well for
    this. It shouldn't take long to find the ticklish spot, at which point you
    can figure out a way to access the solder side of the board and touch up any
    suspect joints. It may take a couple passes but if you can solder and have
    some common sense this should be within your ability to repair.
     
  12. James Sweet

    James Sweet Guest


    You pretty much have to work on it with the power turned on, just shut it
    off and unplug it before you try to solder anything. Usually there's enough
    slack that you can leave the HV anode lead connected to the CRT and not have
    to discharge anything. Just give it a few minutes for capacitors in the
    power supply to discharge and treat them as charged.
     
  13. blanking

    blanking Guest

    Thanks for the great advice, as you say with this advice and a bit of common
    sense I should stand a good chance of fixing it. When it first happened I
    just assumed it was a capacitor problem considering it's age and so was just
    going to abandon it but when it responded to a tap I thought it might be too
    soon to give up on it. The only difficulty at the moment is that the problem
    has settled down a lot, so I will have to wait till it gets more flakey as
    the act of taking the cover off will probably be enough to get it going
    again and at this stage it can keep going for quite sometime before it
    flakes out again which makes faultfinding difficult.
     
  14. Smitty Two

    Smitty Two Guest

    Yes, that's correct, you troll. Make sure you work with both hands, and
    keep one foot in the bathtub.
     
  15. James Sweet

    James Sweet Guest

    Just go for it, when you start poking around, it's very likely the problem
    will occur once you start flexing and tapping things.
     
  16. blanking

    blanking Guest

    Not sure why you think i am a troll, I guess what I said is not totally
    correct and maybe even dangerous, but I always intended to check with a web
    search exactly what to do, all I really know is that the caps will hold a
    dangerous charge which i need to discharge somehow.
     
  17. Smitty Two

    Smitty Two Guest

    Well, I think it's pretty obvious why you're a troll. You keep muttering
    about dust and capacitors and thinking something's loose other than,
    let's say, the things that could possibly be loose. And, continually
    declining to believe what you're being told. If you came hear to be a
    pest, go away. If you came here to learn something, pay attention. You
    may have the ability to triumph over your own ignorance, but it's going
    to take more effort than you've so far exhibited. Do you know what a
    cracked solder joint looks like, how to find one, and how to fix it? No.
    And you aren't interested in taking the time to learn. And, I don't
    blame you. One lousy 12 year old TV isn't worth the bother.

    There's 40,000 volts hanging around in there, and shorting the power
    plug pins together isn't going to do a damn thing to discharge them.
    Getting thrown across the room and bounced off the wall when you touch
    the wrong thing will get rid of part of it, though.
     
  18. Meat Plow

    Meat Plow Guest

    You thought it was the "cathode ray tube."
    Have it fixed by a tech, you don't know enough. Also there are some
    capacitors in that set that should be replaced.

    --
    #1 Offishul Ruiner of Usenet, March 2007
    #1 Usenet Asshole, March 2007
    #1 Bartlo Pset, March 13-24 2007
    #10 Most hated Usenetizen of all time
    #8 AUK Hate Machine Cog
    Pierre Salinger Memorial Hook, Line & Sinker, June 2004
    COOSN-266-06-25794
     
  19. The problem is a little knowledge is likely worse than none, because a bit
    makes you think you know how to fix the problem.

    People have stated what they think the problem is, and you think you
    can define what's wrong by how much of a tap you need to give the set?

    And I don't really know what that nonsense is about shorting things, but
    until you can make sense in that area you shouldn't be going near the insides
    of the set.

    Michael
     

  20. Very wrong, and a good way to die. see: http://www.repairfaq.org/


    No, it isn't. There is a 99.5% probability of a cracked solder
    joint. The other .5% is a damaged connector. If you look closely at
    the solder work on the PC boards you will see more than one cracked
    joint. the more you beat on the TV, the more damage will occur from the
    vibration.


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
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