Speaker system failure analysis
No sound
1. The speaker wire is disconnected or the frequency divider is abnormal. After the speaker wire is broken, the speaker unit has no excitation voltage, which will cause a silent failure. The frequency divider is generally not easy to break, but there may be faults such as lead connector desoldering, frequency division, and capacitor short-circuit.
2. The voice coil is broken. You can use a multimeter to measure the speaker lead wire soldering piece in the R×1 file. If the resistance value is ∞, use a knife to scrape the sealed paint on both ends of the voice coil to expose the bare copper wire before measuring. If it still does not work, it means that the internal voice coil is broken. If the measurement is on and there is a “click” sound, it indicates that the voice coil lead is broken. You can solder the end of the wire, and then use another piece of enameled wire similar to the voice coil winding.
3. The speaker wire is broken. Because the speaker cone vibrates frequently, the braided wire is easy to break, and sometimes the wire is broken, but the cotton core wire is still connected. This kind of braided wire is not easily available and can be replaced by a slightly longer flexible wire.
4. The voice coil is burnt out. Use a multimeter to measure the speaker lead in the R×1 file. If the resistance is close to 0Ω and there is no “click” sound, it means that the voice coil is burned out. Before replacing the voice coil, clean up the debris in the magnetic gap. Then carefully put the new voice coil into the magnetic gap, straighten the voice coil, and fix the upper and lower positions of the voice coil with super glue while listening. After the voice coil is placed in the best position, use super glue to fill the gap between the voice coil and the paper cone to about half. Finally, seal the dust cover, put the speaker cone up, and put it on for a day before it can be used normally.
Intermittent voice
1. The speaker lead is defective. It is usually caused by mold breakage or poor soldering of the voice coil leads. When the paper cone vibrates frequently, the breakpoints will be connected and disconnected from time to time, resulting in irregular and intermittent sound faults.
2. The voice coil lead wire is broken or about to be short-circuited.
3. The power amplifier output jack is in poor contact or the speaker input wire is disconnected.
4. The performance of the speaker is poor, and the magnetism of the magnetic steel is reduced. The sensitivity of the speaker mainly depends on the magnetism of the permanent magnet, the quality of the paper cone and the quality of the assembly process. Ferromagnetic objects can be used to touch the magnetic steel. According to the size of the attractive force, the magnetic strength of the magnetic steel is roughly estimated. If the magnetism is too weak, the speaker can only be replaced.
5. The magnetic core pin is loose. When the magnetic conductive core of the speaker is loose, it will be attracted to one side by the magnetic conductive plate, causing the voice coil to be squeezed to hinder normal sound production. When overhauling, you can lightly press the paper cone with your hands. If you can’t press it, it may be that the voice coil is pressed by the stem, and you need to disassemble and re-fix it before it can be used again.
6. The divider is abnormal. When there is a defective component in the frequency divider, the signal of the corresponding frequency band is blocked, and the speaker of this frequency band has a small volume failure. It is important to check whether the crossover capacitor in parallel with the woofer is short-circuited, and whether the crossover inductor in parallel with the tweeter is short-circuited between layers.
Abnormal sound
1. There is debris in the magnetic gap. If debris enters the magnetic gap, the voice coil will rub against the debris when vibrating, resulting in a hoarse voice.
2. The voice coil wipes the core. The position of the voice coil is not correct, and it rubs against the magnetic core, causing sound distortion. Correct the position of the voice coil or replace the voice coil during maintenance.
3. The paper cone is broken. The paper cone should be replaced if the damaged area is large, and the smaller damaged area can be repaired with a thinner paper cone or other tougher paper.
4. The cabinet is defective. Poor sealing of the cabinet or improper installation of the decorative net cover, etc. This will cause a cracking sound during playback. In addition, if the cabinet plate is too thin, it will cause resonance and abnormal sound.
Speaker maintenance
Prevent dust from contacting the speakers.
This requires special attention during the use of car speakers. For example, in computers, the dust has always been a natural enemy of computers. Many computers have often ignored the powerful lethality of dust in years of use. Finally brought a devastating disaster to my computer. But the speaker is a relatively tight design. The connection line between the speaker and the subwoofer is connected to the speaker by the pin of the cabinet, so if the connection is not smooth, the sound quality of the speaker when playing music will be poor, and it will not be usable when it is more serious. Therefore, we should try our best to keep the speakers free from dust when they are placed.
Moisture-proof
Humidity is the root cause of the physical deterioration of speakers. The horn undergoes physical deterioration during the vibration process, which causes the horn’s diaphragm to age. This directly leads to a decrease in sound quality. In addition, humidity aggravates the aging and breakage of the soft rubber ring of the speaker, and the metal parts in the speaker corrode and rust. Therefore, we need moisture protection.
Clean the knob
The speakers are worn out. A common problem is that noise appears when you turn the volume or tone knob. Sometimes turning the knob several times quickly can temporarily make the noise disappear for a while. But this is not a long-term solution. Open the case, spray circuit cleaner into the potentiometer wiring and the gap, and then quickly turn the knob. If it still doesn’t work, it’s time to change a potentiometer, which can be found in some places where home appliances are repaired, and the price is not expensive. If conditions permit, for example, if you have a professional technician, you can also clean up all kinds of foreign objects remaining in the speaker when you open the box: dust, hair, spider webs, all kinds of mosquitoes, flies, etc., as well as wires and electronic components everywhere’s contact.