Common Failures of Voltage Regulators
Blown Fuse
Generally, a blown fuse indicates a problem with the internal wiring of the power supply. As the power supply works in a high voltage, high current state, the fluctuation of the grid voltage, surge will cause an instantaneous increase in current within the power supply and make the fuse blow. Focus should check the power input rectifier diode, high-voltage filtering electrolytic capacitors, inverter power switching tubes, etc., to check whether this component has a breakdown, open circuit, damage, etc.. If the fuse is indeed blown, you should first look at the circuit board components, look at the appearance of these components have not been burned, there is no electrolyte overflow, if you do not find the above situation, then use a multimeter to measure the switching tube with or without a short-circuit breakdown. Special attention should be paid to: Do not find out when a component is damaged, replace it directly after the boot, so that it is likely that other high-voltage components are still faulty and will replace the component damage, be sure to check all the high-voltage components of the above circuit ** check measurements in order to completely rule out the fault of the blown fuse.
Common faults of voltage stabilized power supply
No DC voltage output or unstable voltage output
If the fuse is intact, there is no DC voltage output at all levels under load. This situation is mainly caused by the following reasons: power supply open circuit, short circuit phenomenon, over-voltage, over-current protection circuit failure, auxiliary power supply failure, oscillation circuit does not work, power supply overload, high-frequency rectifier filter circuit rectifier diode is punctured, leakage of filter capacitors and so on. In the use of a multimeter to measure the secondary components, ruled out the high-frequency rectifier diode breakdown, short-circuit load, if the output is zero at this time, you can be sure that the power supply control circuit failure. If there is a part of the voltage output indicates that the front stage circuit is working properly, 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, which rectifier diode breakdown will make the circuit no voltage output, filter capacitor leakage will cause unstable output voltage and other faults. With a multimeter static measurement of the corresponding components can be checked out of the damaged components.
Poor load capacity of power supply
Poor load capacity of power supply is a common failure, usually in the old or long working time of the power supply, the main reason is the aging of the components, the switching tube is unstable, no timely heat dissipation and so on. Should focus on checking whether the voltage regulator diode heat leakage, rectifier diode damage, high-voltage filter capacitor damage.、、
