Lapel microphone wires without insulation and not conducting?

Discussion in 'General Electronics Chat' started by rg12, Jun 27, 2016.

  1. rg12

    Thread Starter New Member

    Jun 27, 2016
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    0
    I have a lapel microphone that had a mono 3.5mm plug and I bought a TRRS plug to solder
    it instead of the mono plug (for connecting it to my smartphone).

    The thing is, I cut the mono plug, stripped the first insulation to find two wires (obviously) that seem
    to have no insulation while one is bare copper and the other is anodized red copper, each wraped
    with that white fabric.

    The thing is that the white fabric that sometimes goes around the core wire is usually insulating
    between the core wire in the middle and the ground wire wrapped from the outside, but in this case
    it's two bare wires touching each other with no insulation through the whole length of the wire.
    How is that not shorting the wires??

    Also, I have tried to check if they are shorted with my multimeter set to beep on closed circuit,
    so I put one probe on each of the wires and no sound (which seems good, nothing is shorted)
    but then I put the two probes on ONE wire (about 0.5mm apart) and it's not conducting!
    that happens on both conductors that come out of the microphone wire.
    How is that possible? my multimeter does beep when touching both probes together.

    I have done hundreds of small soldering projects in my life (soldering plugs, capacitors etc)
    and never seen a copper wire that doesn't conduct and two conductor wires with no insulation
    inside a microphone wire.

    Would appreciate any help.

    Thanks alot,
    Roy
     
  2. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    The other is not likely NOT anodized red copper. Small speaker wires are often coated with an insulating enamel so they do not short inside the cable. Thus when you try to measure to see if they are shorted, the red is insulating the probe from making contact with the wire. You have to remove this coating before making your measurement or attempting to solder to the wire. This is easily done by inserting the wire in a small flame (a match or lighter) and burning the enamel off. Clean the end with fine emery paper and try your measurements again.

    Here is an article on fixing a broken wire in a headphone that includes similar information.
     
  3. rg12

    Thread Starter New Member

    Jun 27, 2016
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    That is exactly the case I have!
    So do I need to burn the insulation and then solder or I can just solder and the heat of the solder will remove the insulation?
    (it's not rubber insulation, it's like electrocoated anodized insulation of some kind).

    Thanks alot!
     
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,813
    1,105
    As said, you need a small flame to burn off the enamel. It only takes a fraction of a second. Soldering iron temperature isn't high enough generally.
     
    djsfantasi likes this.
  5. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    835
    What Alec said!
     
  6. rg12

    Thread Starter New Member

    Jun 27, 2016
    3
    0
    Thanks alot guys! life savers!
     
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