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Coil replacement

Discussion in 'General Electronics Discussion' started by wdariusw, Sep 14, 2015.

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  1. wdariusw

    wdariusw

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    Nov 10, 2014
    Hi all. I have a headache.. o_O I need to find replacement for car transponder coil... Original coil have about 920uH inductance and about 30 Ohm resistance. There are "replacements" from aliexpress (http://www.aliexpress.com/item/10-p....q90jxt&ws_ab_test=201407_5,201444_6,201409_4) , but when i have bought it, replacement coil have 2.65mH inductance and about 300 Ohm resistance. Transponder do not work with that replacement. There are also one capacitor in paralel without wich transponder do not work with original coil. It is possible to make transponder work with different ( 2.65mH instead 920uH) inductor and parralel capacitor combination than original ? Thanks !
     

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  2. Colin Mitchell

    Colin Mitchell

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    Aug 31, 2014
    How many pins on the coil
     
  3. wdariusw

    wdariusw

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    Nov 10, 2014
    Hello. Like simple coil - 2 pins. Other 2 pins are only for strenght.
     
  4. Colin Mitchell

    Colin Mitchell

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    Aug 31, 2014
    What are you doing? Waving a magnet past the coil?
     
  5. wdariusw

    wdariusw

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    Nov 10, 2014
    I'm trying to fix my another renault laguna key card with broken coil.
     
  6. Colin Mitchell

    Colin Mitchell

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    Aug 31, 2014
    What does the coil do?
     
  7. wdariusw

    wdariusw

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    Nov 10, 2014
    It is transponder coil. Without it car do not start.
     
  8. Colin Mitchell

    Colin Mitchell

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    Aug 31, 2014
    Pull the other coil apart. It is broken at one of the pins
     
  9. wdariusw

    wdariusw

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    Nov 10, 2014
    You do not understand. I want to solder other coil, but THERE ARE NO EXACT REPLACEMENT.
     
  10. Martaine2005

    Martaine2005

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    May 12, 2015
    Hi,
    I think Colin is saying to open the coil in the key fob that is not working.
    It may be broken at the pin connection.
    You may even be able to re-solder it there.

    Martin
     
  11. wdariusw

    wdariusw

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    Nov 10, 2014
    Coil is damaged with soldering iron, can't fix it.
     
  12. Colin Mitchell

    Colin Mitchell

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    Aug 31, 2014
    Use the soldering iron to find the end of the wire.
     
  13. wdariusw

    wdariusw

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    Nov 10, 2014
    I need to find where to buy NEW coil for that card.
     
  14. Colin Mitchell

    Colin Mitchell

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    Aug 31, 2014
    You cannot buy the component. It is called a "HOUSE'" component and its value may be very critical. It could be 100kHz or higher transfer.
    You have to do as I say.
    I have not fixed 35,000 electronic devices because I am stupid.
     
  15. AnalogKid

    AnalogKid

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    Jun 10, 2015
    The economics of large-volume manufacturing are working against you. While it can cost thousands of dollars to have a manufacturer create a custom or modified-standard version of something as simple as an inductor, the custom part might reduce the overall cost of the circuit, and saving only a few cents per assembly can add up to tens of thousands of dollars in savings over a multi-year production run. Because of this, the odds that you will find a drop-in replacement part off the shelf are virtually zero. Try looking for a used device on ebay and scavenge what you need from it.

    ak
     
  16. Nanoamps

    Nanoamps

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    Feb 14, 2011
    Not sure how you know what the correct inductance value is supposed to be, but its not all that difficult to wind your own inductors / coils. There is much information on the web to that. One might need a method of testing your home-built coil to see that its final value is close to your intended spec.
     
  17. Colin Mitchell

    Colin Mitchell

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    Aug 31, 2014
    Inductance is only one attribute to a coil.
    I have an outdoor solar light with two coils (inductors) 0.47mH. One is 4R9 the other is 10R. They cannot be swapped over.
    Inductance means nothing.
    The wire size and ferrite core may also have an effect. It is much quicker to pull the coil apart and find the ends of the wire.
     
  18. Nanoamps

    Nanoamps

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    Feb 14, 2011
    Agreed that coils aren't defined by a single attribute. I think your advice to try to ressurect the existing part is sound repair advice. The poster apparently believes he/she has damaged the part beyond repair.
    There's a few million engineers, however, that wil be quite surprised by your newly defined law where inductance is irrelevant. Not to mention all those R/F circuits that now have to quit working.
     
  19. GPG

    GPG

    452
    66
    Sep 18, 2015
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