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coax cable spark when trying to plug into my plasma

Discussion in 'Plasma TVs' started by kener40, Sep 1, 2009.

  1. kener40

    kener40 Member

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    I just got a new plasma. When I try to hook up the cable either coax or HD cables I get this rather large spark. So I am unable to Watch tv. I can how ever play games and watch DVDs. Does anybody know why the coax cable is sparking when I try to hook it up?
  2. pannyfanny

    pannyfanny Member

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    That is BAD! Coax is not supposed to carry electricity, it carries data or signal information. There is a fault I'm 100% certain. Do not connect it again and get it looked at...
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  3. andy1249

    andy1249 Active Member

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    Either your hotplugging , and/or its an ESD discharge. Hotplugging is inserting or removing cables while any of the units are switched on , and is never a good idea , all cables should be connected up before switching anything on.

    If all equipment is switched off and you are still seeing the spark , then its ESD , which will be coming most likely from yourself , try touching a radiator or something grounded before plugging in the cables.
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    Last edited: Sep 1, 2009
  4. shortshrift

    shortshrift Member

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    It shouldn't be possible for a coax with one end in a healthy set top box to carry a static level that needs to be discharged to ground... the outer conductor in coax _is_ a ground.

    The sparking suggests an earth fault in the TV/STB/mains wiring.
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  5. andy1249

    andy1249 Active Member

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    No , but it is possible for the body to hold such a charge , especially with insulated shoes and a nice plush carpet to walk on ....

    Also , keep in mind that some equipment is not earthed , for example anything powered by a figure of 8 lead has no earth connection , ( Sky HD , most STB's , blu ray players etc ) minor sparking while hotplugging such equipment is common.

    Different equipment can be connected to different grounds as well , meaning there is or could be a voltage difference between grounds on different equipment , that can cause a spark while connecting up. Thats one of the reasons why hotplugging is not such a good idea.

    An electrical fault is of course also a possibility , but usually thats rare enough and should trip some breakers. If its not doing that then were probably talking ESD or some minor charge dissipation.
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    Last edited: Sep 1, 2009
  6. shortshrift

    shortshrift Member

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    I hotplug grounded low-voltage cables (USB, ethernet, RCA audio, ...) all the time without any pyrotechnics. Once in a while there'll be a static discharge between myself and the chassis, but you feel this, so I don't think it's what's being described.

    Yup... if the design doesn't call for it then not connecting earth reduces the likelihood of ground loops. But plasmas with large power draws for high voltage AC panels will be earthed. And a floating earth from a bad socket or poor mains grounding could certainly cause this sparking.

    Based on the poster's statement that "either coax or HD cables I get this rather large spark", I would consider having an electrician check the impedance of the earth.

    Because it sounds like one way or another the ground levels of the TV and the STB are not the same.
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  7. kener40

    kener40 Member

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    The house is old, it only has a 2 Wire electrical wires going to all the outlets.

    I took the tv back to the store and it worked great there.
    A CRT tv works in the house.
    I used to have a Sony Plasma In the same spot i am trying to hook up a new Samsung Plasma, Put I had Dish network, now I have comcast cable.
    You guys have been great giving me ideas

    But I am still not sure where to start 1st.
  8. shortshrift

    shortshrift Member

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    Ah, you're talking about a US setup! AVForums is UK-based, and we have different mains wiring (3-pin sockets with a correctly wired earth are mandatory).

    If it worked in store then the TV is okay, so it is either a wiring problem, or a problem with your Comcast box.

    It might be worth calling Comcast and seeing whether they can suggest anything sensible, otherwise get the TV store to recommend an electrician.
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  9. petet66

    petet66 Member

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    I was just about to post that the OP should immediately leave his house without touching anything electrical before I too realised he was in the US...
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  10. shortshrift

    shortshrift Member

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    Quite - I was briefly shocked (feeble pun intended) until I saw the bit about Comcast! :)
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