Can someone please explain this connection to me?

Discussion in 'The Projects Forum' started by dextro, May 22, 2013.

  1. dextro

    Thread Starter New Member

    Dec 7, 2010
    14
    0
    Hi,

    I am trying to repair a small portable speaker with a broken jack plug for a friend of mine. The cable was damaged and I want to connect a new jack.

    The problem is that the connection is not what I expected. here is a close up picture of the wires connecting to the jack:
    http://imageshack.us/photo/my-images/7/dsc01778fv.jpg/

    I am used to seeing two insulated wired for each channel and a ground wire which is usually around the other two. But in this case there is no plastic insulation, just three wires with what looks like metal on the outside. Could it be that the colors of the individual strands is in fact insulating paint? There is also some white fibers in the center of each wire but I think that is just for strength. I seems the outside of the wires do not conduct if i touch them with my multimeter.

    Do you think it is possible to just solder a jack to these wires? and then how do I identify which wire is which?
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,028
    3,237
    I would think that the outside of the wire is some type of insulating fiber. Not sure if you can solder to the wire. Give it a try. ;)
     
  3. WBahn

    Moderator

    Mar 31, 2012
    17,757
    4,800
    It looks like it might be anodized aluminum foil. If so, you will need to peel it back to expose the conductors. Be careful to not damage the foil or to keep them physically isolated in the new assembly to prevent shorting.
     
  4. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    Actually that is a normal enamel wire in three different colours - plain, red and blue. You need to carefully separate the colours so that you don´t get a short in the end, then get rid of that pesky plastic fibre in between because it usually doesn´t want to melt and simply go away, and then tin each of the strands to get a good connection. The tinning usually takes some time to get rid of the enamel and to get to the copper underneath.

    Plain colour is typically ground, and the two remainig are left and right signals. You can check which one is which by tapping it with for example a 1.5V battery with some 1k-10k resistor in series against ground and see which of the speakers responds to which wire.
     
  5. gerty

    AAC Fanatic!

    Aug 30, 2007
    1,153
    304
    Hard to tell by the pic, but to me it looks like Litz Wire.
    http://en.wikipedia.org/wiki/Litz_wire
    Does it appear to have some sort of thread in the center?
    That stuff is hard to solder, not impossible, but hard.
    The colored insulation has to be removed before soldering, and that process usually destroys the wire.
     
  6. dextro

    Thread Starter New Member

    Dec 7, 2010
    14
    0
    It works again :D
    The strands of the wires were indeed individually insulated. The coating was quite easily removed by tinning the wires.

    Thanks for your help!
     
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