Need to figure out how to replace an electronic component (Invisible fence transmitter box)

Discussion in 'General Electronics Chat' started by dbh211, Nov 29, 2018.

  1. dbh211

    Thread Starter New Member

    Nov 29, 2018
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    A week ago, my invisible fence transmitter box started beeping and wouldn't stop. I have no reason to believe the perimeter fence is compromised.

    I removed this piece and touched the internal connectors into which it plugs with a metal knife blade, and the beeping stopped. I believe this piece (see photo attached) is the culprit.

    Anyone know what this is called / where I can get a new one?

    Thanks!
     
  2. Reloadron

    Distinguished Member

    Jan 15, 2015
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    2,085
    It looks like a connector. Would that be the line to the buried cable? You really need to tell us what according to the user manual the beeping means? If you simply shorted out the connector pins and that is for the loop then possibly yes, the loop is open. or remotely possible the connector is open or intermittent. Your best bet is to contact the manufacturer.

    Ron
     
  3. dbh211

    Thread Starter New Member

    Nov 29, 2018
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    0
    Thanks Ron -

    Yes, it is the line to the buried cable. The beeping means the loop is open. I'm trying to replace this part myself because Invisible Fence charges $100 for a technician to simply show up at my door...

    I inherited the system (no instruction manual). You said "connector" - can you elaborate? I'm a total novice.
     
  4. MrSoftware

    Senior Member

    Oct 29, 2013
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    Is it the job of that piece to connect to the two terminals that you bridged with your knife (short them together)? Can you post any other pictures of that device, or a picture of it plugged in as it normally would be? Are there any markings on it?
     
  5. dbh211

    Thread Starter New Member

    Nov 29, 2018
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    0
    Yes, it connects directly to the two terminals. There aren't any markings. I will take some more pics later when I get home.

    Thanks to all for trying to help me!
     
  6. Reloadron

    Distinguished Member

    Jan 15, 2015
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    OK, working from some memory of my sister's system. When it went in I want to recall they used AWG 18 and that being the wire size with a THN specification which is pretty common everyday wire with insulation suitable for burial. They normally use a single strand of copper rather than multi-strand.

    The part you showed is likely just a molded nylon or plastic connector which connects the buried line to the transmitter. The transmitter, among other things, senses that there is a cable connected to it. Not sure exactly how the transmitter circuit goes about doing that. So the buried cable forms a loop presenting a resistance to the transmitter, we are keeping this simple. The idea being if the loop (underground buried cable) breaks it creates an open circuit to the transmitter.

    Possible problems come along if the buried wire insulation gets a nick on it, especially in moist or acidic soil corrosion will start and eventually eat through the cable. When you short out the leads in the connector you are presenting a low resistance to the source so it "thinks" there is a good cable out there. That connector is just a means of connecting the buried cable to the transmitter and connectors like that seldom fail unless subjected to considerable stress.

    Something you can try, if you have a meter to measure resistance would be measure across the buried cable when disconnected from the transmitter board. While I have no idea what you should see you should not see a really high resistance or open circuit. If the guried cable is AWH 18 THN solid copper we can look up the resistance table, say we have a 200 foot (or whatever length) loop and get an idea. This just involves knowing how to use the meter.

    Ron
     
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