If you have to pay someone to fix them, it would probably be cheaper to buy a new one.
You have little to lose trying to fix them yourself, but you will need at least a multimeter and a soldering iron.
The cable is what generally gets damaged often near the plug or the headphones. See if you can find where the damage is. One method is to open up the headphones and see if you have connections back to the plug from inside. Start with the one that is not working. If you can't get a connection to the plug, go down the cable, looking for damage. If you get to the plug, cut it off and strip the ends of the wires, and try to get a connection back to the headphones., and if so, fit a new plug. Don't forget to put the wire trough the plug cover before you start soldering.
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If you have to pay someone to fix them, it would probably be cheaper to buy a new one.
You have little to lose trying to fix them yourself, but you will need at least a multimeter and a soldering iron.
The cable is what generally gets damaged often near the plug or the headphones.
See if you can find where the damage is.
One method is to open up the headphones and see if you have connections back to the plug from inside. Start with the one that is not working.
If you can't get a connection to the plug, go down the cable, looking for damage.
If you get to the plug, cut it off and strip the ends of the wires, and try to get a connection back to the headphones., and if so, fit a new plug.
Don't forget to put the wire trough the plug cover before you start soldering.