Diagnose the problem
Are they broken at the plug or the speaker? Plug them in, turn the music on and wiggle the wire near the plug. If you hear a crackle (or they go off completely), you probably need to replace the jack plug. Repeat near the speaker – a crackle after a wiggle at that end means you need to repair the speakers.
Changing a jack plug
Cut the old jack plug off using wire cutters. If your headphones consist of two adjoining cables, gently pull 4cm of the cables apart and strip the same amount of outer insulation from the end of both cables. If you have single-cable headphones, strip 4cm from the outer insulation
If you have two cables, one will contain two unshielded copper ground wires, the other will contain two insulated signal wires, the left signal (white) and right signal (red). Single-cable headphones will usually contain one copper ground wire and two insulated signal wires.
Use the wire cutters to strip 5mm of insulation from both signal wires. If necessary, twist the two unshielded ground wires together.
Regardless of your variety of headphones, you should now have three exposed wires at the end of the cable: left signal, right signal and ground.
Use the soldering iron to “tin” (see box, right) each wire. Add just enough solder to cover the wire evenly, not so much that the solder starts to form blobs.
Unscrew the case from the replacement jack plug. Slide the outer case along the headphone wire, with the threaded end closest to the solder joint.
Now solder the wires to the tags (or pins) on the exposed innards of the jack plug. Solder the longest pin (known as the ground pin) to the ground wire. Solder the two signal wires on to the two shorter pins. Crimp the end of the ground tag so that it grips the wire and screw the outer case back to the jack plug.
Test the headphones. If you get no sound, unscrew the outer case of the jack plug and recheck your solder joints. Make sure you have not soldered two wires together, and that no wires have come loose. None of the wires should be touching. If in doubt, use the soldering iron to remove the wires and repeat this process.
Repairing the speakers
To get to the speakers open up the headphones (the bits next to your ears). Some use screws to hold the headset together, others use plastic clips or glue. To open the former, use an appropriate screwdriver. To open the latter, use a craft knife. Push the blade between the glued seams and gently lever the two pieces of the joint apart. Slowly work the blade around the joint until the two pieces crack apart. Sometimes the glue will be too strong and you will not be able to open the joint without damaging the plastic case. But remember: you are trying to fix something that is already broken, so don’t be too upset. You can glue this back together.
Gently remove the speakers. these are round and face the position of your ear. The speakers will have the headphone wires soldered on to them. Look for any damage or detached wires. A detached wire will be floating around inside the case, and there will be a silver tag on the speaker that no longer has a wire attached to it. Cut back the end of the wire by 5mm and remove the outer plastic insulation using wire strippers.
Apply a little molten solder to the exposed wire, and then attach it to the silver solder tag on the speaker by melting the solder on to the tag with the iron, and touching the wire to the tag before the solder cools. Remember: heat will travel up the wire, so avoid holding the soldering iron in place for any longer than necessary.
Damaged wires that haven’t become disconnected should still be easy to spot: they will have kinks in them, or the damaged section will be a different colour to the rest of the wire. The colour change occurs if wires have been stretched. Desolder the wires from the speakers by applying the iron to the solder tags on the speaker and gently pulling the wires clear of the molten solder.
Remove the damaged section of the wire with wire cutters – try to cut an extra couple of inches further back from the visible damaged section, just in case the damage has said.
Strip the wires using wire cutters and tin the exposed ends of the wire with solder. Resolder the wires on to the headphones. It should be easy to spot where the wires need to be soldered, since there will be only two solder connections on the speaker, and there should be two wires connected to it.
Screws should be screwed back in place and headphones that were clipped or glued together should be reclipped and held in place with superglue.
Soldering masterclass: carry out your own electrical repairs
• A soldering iron (£10.98): power of a soldering iron is measured in watts – the higher the wattage, the sooner the iron will get hot. A 20-watt iron is fine for most general soldering jobs.
• A solder sucker (£1.65, from mptools.co.uk): this removes excess solder by sucking the molten solder away from the tip of the soldering iron. Push down the lever at the end of the solder sucker, melt the excess solder with a soldering iron and position the nozzle of the solder sucker near the molten solder. Click the button on the side and the lever will shoot upwards, sucking the excess solder into the reservoir.
• Soldering iron tip cleaner: you can buy these ready-made, but a metal scouring pad in an empty tuna tin is just as effective. Repeatedly dip the end of your soldering iron into the metal scouring pad – any excess solder or dirt will be removed in seconds.
Here’s the secret to soldering: rather than melting the solder with the iron, heat the object you want to solder so that it is that object that melts the solder directly when applied.
To make a good solder joint between two wires, strip back the plastic sheath from the wires and heat the exposed metal with the soldering iron. Apply solder to the heated metal wire. The solder should flow readily on to the metal wire if it is hot enough. As soon as the solder flows, remove the soldering iron from the wire and let the solder cool. This process is called tinning.
Tin the other wire so that both exposed pieces of metal wire have solder on them, and position them so that the two soldered sections are touching. Apply a little solder directly to the tip of the iron, and then touch the iron to the point where the two wires touch. Remove the iron as soon as the solder melts on the wire. When the solder cools, the two wires should be soldered together. Clean the tip of the iron using a soldering iron tip cleaner and unplug the iron. Allow the iron to cool before packing away.
The process of tinning applies to all soldering, whether it is wires or components on a circuit board. Apply the solder to the both surfaces first, then remelt the solder when the surfaces are touching. Excess solder can be removed with a solder sucker.