What are the common failures of LED switching power supply?

What are the common failures of LED switching power supply?

The fuse blew out

In general, the fuse circuit breaker explains the internal wiring of the power supply. Since the power supply is in high voltage and high current state, the voltage fluctuation of the power grid will cause the current in the power supply to increase instantly and fuse the fuse. The key should check the rectifier diode of the power input terminal, the high voltage filter electrolytic capacitor, the inverter power switch tube, etc., and check whether the component has any breakdown, opening, damage, etc. If it was blown fuse, should first check the circuit boards of each element, see the appearance of all these components have to be burned, is there any electrolyte overflow, if did not find the above situation, the switch tube with or without breakdown short circuit is measured with a multimeter. Need to pay special attention to is: not in found to a certain element of damage, replace directly after boot, this is likely due to the high pressure components are defective and will replace the element damage, must all high voltage to the circuit components to conduct a comprehensive inspection measure, can completely eliminate the malfunction of blown fuse.

No DC voltage output or voltage output instability

If the fuse is intact, there is no output of dc voltage at all levels under load conditions. This situation is mainly due to the following reasons: short circuit fault, open circuit fault phenomenon occurring in a power supply, the overvoltage and overcurrent protection circuit malfunction, auxiliary power supply failure, oscillation circuit without work, the power load is overweight, high frequency rectification filter circuit in the rectifier diode is punctured, the filter capacitor leakage, etc. In secondary element is measured with a multimeter, ruled out high-frequency rectifier diode breakdown, load short circuit, if the output is zero at this moment, you can definitely is a fault in the power control circuit. If partial voltage output indicates that the front level 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 pressure filter capacitor dc voltage output, including rectifier diode breakdown can make the circuit no voltage output, output filter capacitor leakage will cause the voltage instability of fault. The component can be checked for damage by using a multimeter static measurement of the corresponding element.

Poor power load capacity

The power load capacity is a common fault, are generally appeared in the old or work long time power supply, the main reason is that the components ageing, switch tube is not stable, not in a timely manner heat dissipation, etc. It is important to check whether the stabilized diodes have the heat leakage, the rectifier diode damage, the high voltage filter capacitance damage, etc.

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