Power supply failure accounts for the majority of electronic equipment failure in electrical fault repair. Therefore, being familiar with the quad output switching power supply
common faults and maintenance skills is conducive to shorten the maintenance time of electronic equipment fault, improve personal equipment maintenance skills. The common quad output switching power supply
failures are as follows:
(1) Blown fuse:
In general, fuses indicate a problem with the internal wiring of the power supply. As the power supply works in the state of high voltage and large current, the fluctuation and surge of the power grid voltage will cause the instantaneous increase of the current in the power supply and make the fuse fuse.
(2) The no dc voltage output or voltage output is not stable
If the fuse is intact, there is no output at all levels of dc voltage under load. This situation is mainly caused by the following reasons: open circuit, short circuit, over voltage, over current protection circuit fault, auxiliary power supply fault, oscillation circuit not working, power supply load being too heavy, high frequency rectifier filter circuit rectifier diode breakdown, filter capacitor leakage, etc..In the use of a multimeter measurement of secondary components, excluding the high frequency rectifier diode breakdown, load short circuit, if the output is zero at this time, it can be sure that the power supply of the control circuit out of the fault. If some voltage output indicates that the front circuit works normally, the fault is in the high-frequency rectifier filter circuit. High frequency filter circuit is mainly composed of rectifier diode and low voltage filter capacitor dc voltage output. Rectifier diode breakdown will make the circuit no voltage output and filter capacitor leakage will cause output voltage instability and other faults. The damaged component can be detected by static measuring the corresponding component with a multimeter.
(3)The power load capacity is poor
Power load capacity is a common failure, generally appearing in the old or long working time in the power supply. The main reason is the aging of the components, the instability work of the switch tube and not in a timely manner for heat dissipation. It is necessary to check whether the voltage stabilizing diode is heating and leakage, the rectifier diode is damaged, and the high voltage filter capacitor is damaged.