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I have repaired earphones a lot of times before. I was very confident that I can do it with any earphone. My friend happen to give me one to repair, Its from a company called KDM.
The problem is the jack but there is something weird. The earphones I have fixed have one red/green or blue colour wire and a copper color ground wire for each earbud. This one is a little weird as it has 1 red wire, 1 blue wire and 1 green wire and 1 copper color wire. I am having trouble identifying the other ground wire. I apparently did a check for continuity using a multimeter and found blue and green to be pairs and red and copper color to be pairs, but the continuity test could not tell me which of the wire blue or green is ground. Google wasnt much help either as all discussed the two copper and two color wires and not the ones I am having.
So my question is : Which of the wires is ground:Blue or Green?

I was thinking of powering the two wires, giving them appropriate voltage and checking which is which, I am worried if the reverse flow of current may damage the speakers..Should I be worried?

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schematic

simulate this circuit – Schematic created using CircuitLab

If you have identified two non-connected pairs the hook them up as shown. Play some music and have a listen. If they are out of phase you will get an odd "hole-in-your-head" sensation. Swap the wiring on one of the ear-pieces and try again. Normal stereo panorama should result.

Alternatively, if you can actually see the diaphragms on the earphones then you could apply a low voltage - maybe 1.5 V and see which way the diaphragm moves. Wire both in-phase.

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  • \$\begingroup\$ Hey! Thanks that actually worked, they used the blue wire instead of more generally seen copper wire as the ground wire thanks again. \$\endgroup\$ – Aaditya Sahay May 28 '16 at 12:04
  • \$\begingroup\$ Did you hear the "hole-in-your-head" out of phase sound? It's weird. \$\endgroup\$ – Transistor May 28 '16 at 12:06
  • \$\begingroup\$ No I did not, The very first attempt did the trick \$\endgroup\$ – Aaditya Sahay May 28 '16 at 12:41
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There is no standardized color scheme for audio lines in a head phone.

It's a very common phenomenon that headphone wires break (in fact, that's far more often than the actual speaker breaking), so just replace the whole wire.

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  • \$\begingroup\$ Instead I was thinking of powering the two wires to see which is which, but was worried if I would damage the speaker of the current's flow in opposite direction. Should I be worried? \$\endgroup\$ – Aaditya Sahay May 28 '16 at 11:53
  • \$\begingroup\$ depends. usually, no. \$\endgroup\$ – Marcus Müller May 28 '16 at 11:55
  • \$\begingroup\$ See @transistor's excellent answer on what happens when you swap polarity. \$\endgroup\$ – Marcus Müller May 28 '16 at 12:03

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