Help identifying positive and negative please.

Discussion in 'TV & Satellite' started by Badknee, Jun 20, 2016.

  1. Badknee

    Badknee Funster

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    bought a freeview recorder at the weekend so that we can load it up here and watch when away. I was expecting it to be 230volts which is ok but delighted to find its 12v.

    Now the question, I want to cut the transformer off the power cable but wondering which might be the positive and which the negative?

    Any ideas please as its not colour coded?

    image.jpeg
     
  2. Chris

    Chris Funster Life Member

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    eeny, meeny, miney mo....


    Works for me.

    Well, roughly half the time it does.
     
    Last edited: Jun 20, 2016
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  3. MH 55 FUN

    MH 55 FUN Funster

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    Can you get the plug apart ?
     
  4. eddievanbitz

    eddievanbitz Trader - Funster

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    cut the transformer off and send it to me.
     
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  5. SomeoneElse

    SomeoneElse Funster

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    Isn't there a little diagram on the unit, near the connector?
    Or else in the manual.
     
  6. Techno

    Techno Funster Life Member

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    Test the end before you cut it off
     
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  7. tonka

    tonka Funster Life Member

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    The centre pin is 99% of the time the +ve.
    Do you have a multimeter ?? If so you can use that the find out..

    Also as said above, it's often shown near the socket the plug connections. Once the wire is cut you can use the multimeter to establish which wire goes to the center and which is the outer -ve..
     
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  8. eddievanbitz

    eddievanbitz Trader - Funster

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    if your new box goes "pop"

    its wong:Eeek:
     
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  9. Badknee

    Badknee Funster

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    Yes Andy I thought of that but will it tell me which is - and which +?
     
  10. ****

    **** Read Only Funster

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    Would the one with the tracer not be live?
     
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  11. Badknee

    Badknee Funster

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    You Mr Bitz are as much use as a hole in a condom. :eek::LOL::LOL::LOL:
     
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  12. Techno

    Techno Funster Life Member

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    If you put your red probe on the centre and black on the outer it will either read a voltage or a minus voltage -12V if it reads minus it is reversed.
     
    Last edited: Jun 20, 2016
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  13. ****

    **** Read Only Funster

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    Or open the box up and see where the wires go. The live one may have a little glass fuse
     
  14. Techno

    Techno Funster Life Member

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    Not reliable enough.
     
  15. Badknee

    Badknee Funster

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    Tha
    ts what I don't know for sure and @eddievanbitz has been on the piss since 10am and I can't get a sensible answer out of him. :whistle:
     
  16. Techno

    Techno Funster Life Member

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    Once you know which is the positive for sure you can then do a continuity test after cutting it off
     
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  17. Badknee

    Badknee Funster

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    The box and the plug are sealed that's why I me stumped :(
    I'll dig out my multimeter. (y)
     
  18. ****

    **** Read Only Funster

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    Aye. Stick a pin through the one with the tracer and see if you are getting 12v running up it. I think the units case should work as a ground unless plastic.
     
  19. Techno

    Techno Funster Life Member

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    image.jpeg
     
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  20. ****

    **** Read Only Funster

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    Good call. I was presuming the cable went straight in to the casing.
     
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