The problem caused by capacitor damage is the highest in electronic devices, with electrolytic capacitor damage being the most common. Capacitor damage is reflected in:

1. Reduced capacity 2. Completely lose capacity 3. Leakage 4. Short circuit

Capacitors have different effects in circuits, and the problems they cause also have their own characteristics. In industrial control circuit boards, digital circuits account for the vast majority, with capacitors mostly used for power filtering and less used for signal coupling and oscillation circuits. If the electrolytic capacitor used in a switching power supply is damaged, the switching power supply may not vibrate and there may be no voltage output; Perhaps the output voltage filtering is not good enough, and the circuit may experience logic disorder due to unstable voltage, which is reflected in the machine working well or not working properly. If the capacitor is between the positive and negative poles of the digital circuit power supply, the problem is reflected in the same way. This is particularly evident on computer motherboards. Many computers have been in use for several years and sometimes fail to turn on the machine, while others are able to turn on the machine. Opening the chassis often reveals the phenomenon of electrolytic capacitors bulging. If the capacitance is removed and measured, it is found to be much lower than the actual value. The lifespan of a capacitor is directly related to the ambient temperature, and the higher the ambient temperature, the shorter the lifespan of the capacitor. This rule applies not only to electrolytic capacitors, but also to other capacitors. So when searching for faulty capacitors, it is important to pay attention to capacitors that are closer to the heat source, such as capacitors near heat sinks and high-power equipment. The closer they are to them, the greater the likelihood of damage. I used to repair the power supply of an X-ray flaw detector, and the user reported that smoke was coming out of the power supply. After opening the chassis, it was found that a 1000uF/350V large capacitor had oily material flowing out. After removing it, the capacity was only a few tens of uF, and it was also found that as long as this capacitor was closest to the cooling fin of the rectifier bridge, the other ones that were far away were intact and had normal capacity. Other ceramic capacitors have short circuits, and it has also been found that the capacitors are relatively close to the heating components. So there should be some emphasis on maintenance and search