Speaker lead wires are flexible braided wires that connect a speaker's terminals to a speaker's cone. From time to time, speaker lead wires wear down, break or loosen into an intermittent or open circuit, causing a speaker to stop working or work poorly. This is a relatively common problem, especially in older speakers. To repair it, you will need to open the speaker box and replace the speaker lead wires.
Remove the problem speaker and test its circuit for continuity using a multimeter. A healthy speaker circuit will measure between 3 and 14 Ohms DC. While applying the multimeter, also gently move the speaker cone up and down and gently jiggle the lead wires back and forth, looking for broken or frayed wire. During this test, if the circuit is open or intermittent, the lead wire circuit needs to be repaired.
Check to see whether your speaker terminals use a crimp instead of solder. In the case of crimp terminals, loosen the crimps with a screwdriver and remove the damaged or frayed lead wires. Most speaker terminals are soldered, though. Using a soldering iron and a solder pump (also called a solder sucker), desolder the existing speaker lead wires from the terminal. Heat and suck up any excess solder. Follow the lead wires to the back of the speaker. The wires terminate either in a connection with a metal eyelet appended to the cone or they disappear into the cone. If connected to a metal eyelet, desolder this end of the leads also, making sure to suck up excess solder. If the lead wire ends inside the cone with no external solder termination, move on to the next step.
Remove the dust cap from the speaker cone--only if the speaker lead wire terminates inside the speaker cone. Cut off the dust cap carefully with a utility or hobby knife, because it will need to be glued back on later. Once the dust cap is removed, the other end of the lead wire can be found, usually soldered to the voice coil wire and glued to the inside neck of the speaker cone. Use the soldering iron and soldering pump again to melt this connection gently and detach the speaker lead wire. Be careful not to damage the thin voice coil wire.
Solder the new strand of lead wire to the voice coil connection if you removed the dust cap to get inside the cone neck. Run the wire out of the cone and to the speaker terminals, but do not attach the other end yet. Using the epoxy, glue this connection back to the neck of the cone. Re-glue the dust cap back on using basic water-based white glue. If you did not need to remove the dust cap to access the lead wire, move on to the next step.
Solder the new strand of speaker lead wire to the eyelet on the back of the speaker cone if you did not need to remove the dust cap. Run the other end of the wire to the speaker terminals, but do not attach it yet. Be sure to use a length of speaker lead wire just long enough to allow a little slack. You need to leave enough slack so that the speaker cone can move up and down without pulling or straining the lead wire. Test the amount of slack by pressing the speaker cone up and down, just as you did when testing for continuity earlier.
Solder the other end of the speaker lead wire to the speaker terminals. Please note the Tips regarding soldering techniques.
Use a multimeter to test the circuit you have just repaired before placing the speaker back in its speaker box.
When soldering, do not use the soldering iron to melt the solder directly. This method is too hot, messy and unreliable. Touch the soldering iron to the terminal, then touch the solder to the terminal and wires. The heat transferred from the soldering iron to the terminal should melt the solder.
Use a soldering iron in a well-ventilated area. Inhaling the smoke from soldering can be very unpleasant and unhealthy.