1. The speaker wiring is broken or the frequency divider is abnormal

After the speaker wiring is broken, the speaker unit has no excitation voltage, which will cause a silent fault. The divider is generally not easy to break, but may have lead joint desoldering, frequency divider capacitor short circuit and other faults.

2. Broken voice coil

Available multimeter R × Measure the loudspeaker lead out lug of gear 1. If the resistance value is ∞, use a knife to scrape off the sealing paint of the leads at both ends of the voice coil. After exposing the bare copper wire, measure again. If it is still not connected, it means that the voice coil is broken internally; If the measurement is turned on and there is a "click" sound, it indicates that the voice coil lead is open circuit. You can solder the wire head and then use another section of enamelled wire close to the voice coil winding wire to solder it.

3. The loudspeaker lead is broken

Due to frequent vibration of loudspeaker paper cone, the braided wire is easy to break, sometimes the wire is broken, but the cotton core wire remains connected. This kind of braided wire is not easy to purchase and can be replaced by a slightly longer flexible wire.

4. Burned voice coil

Use multimeter R × Measure the loudspeaker lead at gear 1. If the resistance is close to 0 Ω and there is no "click" sound, the voice coil is burnt. Before replacing the voice coil, first remove the impurities in the magnetic gap, then carefully put the new voice coil into the magnetic gap, straighten the voice coil, and use super glue to fix the upper and lower positions of the voice coil 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 basin to about half. Finally, seal the dust cover, and put the speaker paper basin upward. After one day, it can be used normally.