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vga and hdmi from pc causes sparks

Discussion in 'HDTV discussion' started by ghost360, Jan 5, 2011.

  1. ghost360

    ghost360 Member

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    Hi all
    When I try to connect my pc to my insignia ns-lcd32-09 with both vga or hdmi I get a relatively large spark, now both my pc and tv are unplugged.
    I have my xbox360 connected to the same hdmi port with no problems.

    My pc specs are ATI Radeon HD 5770, 500w psu, 2gigs ram, 2.8ghz dual cpu.
    Please any advice would be greatly appreciated.
     
  2. ghost360

    ghost360 Member

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    Ok heres an update, I found that my cable box is the culprit so now the only way to have my pc connected to my tv is to have the cable box disconnected.

    Now I dont want to have to rearrange everything when I want to watch tv, my cable box is 2 prong like most I would imagine and I have 3 splitters before my box, I dont know if that has anything to do with it but when its not connected I have no problems.

    anybody have any suggestions on a workaround.

    Thanks
     
  3. attar

    attar Senior member

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    Can you measure voltage on the cable box chassis when it's plugged in?
     
  4. ghost360

    ghost360 Member

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    No I dont have the tools for that, I could probably get them but it would take a few days.

    I was reading somewhere that it might need grounded, now im not sure if that makes sense or nor since it doesnt even have a third prong for grounding. I dont know any help appreciated Thanks.
     
  5. yimmmy

    yimmmy Regular member

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    yes you need to make sure everything inside your pc is grounded, if its physical sparks your talking about that can be a huge problem for your pc. i wouldnt plug it back in until your sure everything inside your pc is grounded.
     
  6. mike.m

    mike.m Regular member

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    Because your cable box only has a 2 prong, AND it sparks, not only does it means it is not grounded, it means the insulation on the cable box/chassis is faulty. The insulation is there so that a ground wire is not needed.

    Exchange for a new one, don't plug that thing back in. And it would not be very smart to try and “ground” the cable box yourself. Not only would you really need to know what you are doing if changing from a 2-wire to a 3-wire, you will void the warranty and you could introduce many more hazards. And if a fire occurs, you won’t be able to blame this on the manufacturer.

    It's probably safer to test resistance/continuity instead of test for potential difference (voltage on a live circuit). If you really wanted to test the resistance between your cable box and the 2-prongs, then you will need a volt-meter for that, and reliable models aren't extremely cheap. Which is why it would be a lot better/safer to just bring it back.

    To do this, you need to connect (touch) one lead of the volt-meter to the cable box chassis, and connect the other one to the (hot) prong of the cable box. The larger prong is the neutral, the smaller one is the hot. And set the setting to read Ohms (resistance/continuity) and if you get a reading of Zero Ohms, then yes your cable box chassis is being short circuited. Don’t worry about polarity when reading Ohms though. Also DO NOT plug the prongs in an outlet when taking measurements for resistance, the circuit MUST be disconnect from the source, because when set on Ohms reading the voltmeter runs on its own internal battery and connecting it to a live source......in short, you will have serious problems. Most digital Voltmeters are dummy proof in case something like this happens, but you still shouldn’t do it, especially with an Analog meter (if anyone still uses those beside reading pulses in AC circuitry).
     
    Last edited: Jan 19, 2011
  7. ps355528

    ps355528 Regular member

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    It's not actually a case of a leak.. double would isolated equipment tends to "float" at around half mains potential.. if the case/chassis isn't grounded.. just grounding the box (they should be grounded by the cable shield connection normally) will solve the problem. If it's not a double wound power supply the old trick was reversing the mains plug.. because one pole of the mains is tied to ground at the supply side.

    If your street is supplied by overhead wires go outside and have a look at the power poles.. notice how there are 3 wires.. 2 phases and a ground.. each alternate house is taken from one hot or the other to balance the load on the 3 wire feed.
     
    Last edited: Jan 19, 2011
  8. KillerBug

    KillerBug Active member

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    There are 3 wires, but ground isn't up there. The third wire is "Common", the other two wires make up 220V, and either wire plus common is 110v (at least in the US). Ground goes to the GROUND...that is, that dirty thing under your house that some people call earth. It is meant as a patch for overloads and spikes...not for normal operation.

    Honestly, I would expect at least one AD member to know how electricity works.
     

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