Switching Power Supply Manufacturers

Switching power supply manufacturers Eahunt electronic engineers to analyze the direct cause of insurance meltdown in the switching power supply:

Switching tube \ power thick module \ rectifier diode breakdown \ 100uf/400v large capacitor breakdown leakage, demagnetization resistor internal fragmentation.

The most common reasons for the switching power supply always no voltage output at all outputs: AC 220v rectifier filter circuit in the insurance resistor open circuit; switching tube base to the 100uf/400v large filter capacitor between the positive pole of the resistor open circuit.

Switching power supply only in the boot moment has a small voltage output of common causes: line output tube breakdown, switching power supply in the switching transformer a left 2.2uf ~ 100uf electrolytic capacitor failure leakage.

Switching power supply output voltage is low for the most common reasons: line output transformer local short circuit pulse width modulation circuit in the transistor and diode breakdown "leakage" opto-coupling device in the transistor leakage.

Caused by the grating and image S distortion and there are two vertically moving black band causes: 100UF?400V large filter capacitor failure and capacity decline.

Caused by the grating local color spot and image local color is not the right reason: is the switching power supply AC 220V input circuit in the resistance open circuit.

Switching power supply manufacturers Ming for electronic engineers to teach you switching power supply no output overhaul techniques:

1, switching power supply always no voltage output reasons

Switching power supply is always no voltage output refers to the switching power supply outputs, in the power switch after the power switch is always 0V, this situation is due to the switching power supply is not generated by the oscillation. Further confirmation of the method is to measure the switching power supply 100UF/400V capacitor voltage after shutdown, if the 300V after a slow decline, then the switching power supply does not produce oscillation. Switching power supply does not produce oscillation for the following reasons:

(1) switching tube collector does not get enough working voltage

(2) The base of the switching tube does not get the starting voltage and the related circuit leakage

(3) switching tube positive feedback component failure

2、Methods and steps to determine the fault

Repair this type of failure is the first task is to determine the drum barrier in the above three parts of which parts, the specific method is to measure the switching tube collector, base voltage, there may be the following cases:

(1) switching tube collector voltage of 0V and lower than the utility 1.4 times, the switching tube does not have a normal operating voltage, if there is 1.4 times the voltage, indicating that the switching tube collector with a normal operating voltage, indicating that the AC220V and rectifier and filtering circuits work properly.

(2) switching tube base voltage of 0V (including power-on moment) This situation indicates that the start-up circuit of the switching tube base does not provide a start-up (conduction) voltage, or the base and the emitter of the relevant components between the breakdown, should be the start-up circuit and the switching tube emitter and the relevant components to check, if the voltage is 0.6 to 0.7 (including power-on moments), indicating that the start-up circuit and the switching tube emitter components are normal, if the start-up circuit and the switching tube emitter components are normal, if the voltage is above 0.7V, the start-up circuit has normal working voltage, indicating that AC220V and rectifier filter circuit is working properly. If the voltage is 0.7V or above, it means that the starting circuit is normal, but the switching tube emitter junction or its components are disconnected or the resistance value becomes large.

(3) switching tube with conduction conditions: switching tube base voltage of 0.6 ~ 0.7V, collector voltage greater than 250V, indicating that the switching tube has the working conditions, the fault is in the positive feedback circuit, including positive feedback resistance, capacitance, current-renewal diode and the switching transformer positive feedback winding and its connection should be made between the board.

So it is also important to choose the brand of switching power supply, want to know more about switching power supply information, you can consult Xiamen Eahunt Electronics.

Whatsapp:+86 13860786068

Email: athene-cai@eahunt.com

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