The speaker system is one of the important components of audio equipment, and usually consists of speakers, crossovers, cabinets, and sound-absorbing materials. The speaker system has a lower failure rate and fewer types of failures. There are four common types of failures.
1. The speaker wiring is broken or the crossover is abnormal. After the speaker wiring is broken, there is no excitation voltage on the speaker unit, which will cause silent failure. The frequency divider is generally not easy to break, but failures such as lead joint desoldering and short circuit of the frequency division capacitor may occur.
2. The voice coil is broken. Multimeter R × 1 level can be used to measure the lead wire of the speaker. If the resistance value is ∞, use a knife to scrape off the sealing paint on the ends of the voice coil to expose the bare copper wire. Broken wire; if the measurement is conducted and there is a "click" sound, it indicates that the voice coil leads are broken. Solder the wire end, and then use another piece of enameled wire close to the voice coil winding.
3. The speaker leads are broken. Due to the frequent vibration of the speaker cone, the braided wire is easily broken, and sometimes the wire is broken, but the cotton core wire remains connected. This braided wire is not readily available and can be replaced by a slightly longer flexible wire.
4. The voice coil is burned. Use a multimeter R × 1 position to measure the speaker leads. If the resistance value is close to 0Ω and there is no "click" sound, the voice coil is burned out. Before replacing the voice coil, you should first remove the impurities 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 strong glue while listening to the test. After the position, fill the gap between the voice coil and the paper cone to about half with strong glue. Finally, seal the dust cover, and place the speaker paper cone upward, and it can be used normally after one day.
Second, sometimes there is no sound
1. Defective speaker leads. It is usually caused by broken mold leads or poor welding of the voice coils. When the paper cone vibrates frequently, the breakpoints are sometimes turned on and off sometimes, resulting in irregular sounds and no sounds.
2. The voice coil leads are disconnected or short-circuited.
3. The power amplifier output socket has poor contact or the speaker input cable is disconnected.
Third, the volume is low
1. The speaker performance is poor, and the magnetism of the magnetic steel decreases. 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, and the magnetic strength of the magnetic steel can be roughly estimated according to the size of the attraction. If the magnetic is too weak, you can only replace the speaker.
2. The magnetic core post is loose. When the magnetically conductive core of the loudspeaker comes loose, it will be attracted to the side by the magnetically conductive plate, causing the voice coil to be squeezed and preventing normal sound. During maintenance, the paper cone can be pressed lightly by hand. If it is not pressed, the voice coil may be pressed by the stem. It needs to be disassembled and re-fixed before it can be used again.
3. The frequency divider is abnormal. When there are bad components in the frequency divider, the signal of the corresponding frequency band is blocked, and the speaker of this frequency band has a small volume fault. Should focus on checking 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.
Fourth, the sound is abnormal
1. There is debris in the magnetic gap. If foreign matter enters the magnetic gap, the voice coil will rub against the foreign matter when the voice coil vibrates, resulting in a hoarse voice.
2. Voice coil wiper. The voice coil is not in the correct position, and it will collide with the magnetic core, which will cause sound distortion. Correct the voice coil position or replace the voice coil during maintenance.
3. The paper cone is cracked. If the damage area is large, the paper basin should be replaced. If the damage area is small, it can be repaired with a thinner paper basin or other tough paper.
4. The cabinet is bad. Poor sealing of the cabinet or inadequate installation of the decorative mesh cover may cause cracking during playback. In addition, the box material is too thin to cause resonance, which will also cause abnormal sound.