Causes of capacitor failure and repair methods

Component open circuit

After the capacitor is open circuit, it has no function as a capacitor. After capacitors in different circuits have open-circuit faults, the specific fault phenomena of the circuits are different. For example, hum sound occurs after the filter capacitor is opened, and there is no sound after the coupling capacitor is opened.

Component breakdown

After the capacitor breaks down, it loses its function as a capacitor. There is a path between the two pins of the capacitor. The DC blocking function of the capacitor disappears, and the DC circuit of the circuit fails, thus affecting the AC working state.

Component leakage

When the capacitor leaks, the insulation performance between the two plates of the capacitor is reduced. There is a leakage resistance between the two plates. DC current passes through the capacitor. The DC blocking performance of the capacitor becomes worse and the capacity of the capacitor decreases.When the coupling capacitor leaks, it will cause high circuit noise. This is a fault with a relatively high incidence rate among small capacitors, and fault inspection and testing are difficult.

Breakdown after energization

The capacitor breaks down after applying the working voltage, and does not show breakdown after the power is turned off. It does not show the characteristics of breakdown when checked and measured with a multimeter. When the power is on, the DC voltage measured across the capacitor is zero or very low, and the capacitor performance deteriorates.

Repair methods

1. If the capacitor has an internal open circuit, replace the components; if the capacitor's external connection is open, re-solder it.

2. Capacitor breaks down, buy new capacitor.

3. Capacitor leaks, buy new capacitor.

4. If it breaks down after power is applied, buy a new capacitor.