Inverter switching power supply maintenance basic method steps

  Inverter switching power supply maintenance six major method steps

      1. Detect whether the rectifier circuit D1—D4 is broken or broken, whether the capacitance of the filter circuit is damaged, whether the balance resistors R1 and R2 are normal, whether the step-down resistor R3 is blown or the resistance value increases (test under power failure).

      2. Detect the rectifying and filtering components of the secondary output winding, and focus on whether the filter capacitor is bulged or damaged to eliminate the possibility of short circuit of the secondary circuit.

      3. In the case of determining that the above components are normal, we can remove the switching power supply board from the inverter and perform a power-on test separately. Use the voltage regulator to slowly adjust to the rated voltage of the switching power supply. At this time, you should be able to hear the hum of the transformer when starting up. If you do not hear the sound of the starting vibration, use a multimeter to check the positive and negative power of the UC3844. Is there a DC voltage of around 12V-16V?

      4. Detect whether the b-e junction and the c-e junction of the switch tube have a breakdown short circuit, and measure whether the windings of the switch transformer have a short circuit to determine whether the switch tube and the switch transformer are good or bad (tested under power failure).

      5. After determining the voltage of the power supply terminal of UC3844 is normal, you can use the oscilloscope to check whether the 6-pin PWM wave is output to the trigger end of the switch tube. (Depending on the circuit design, the frequency of the PWM wave is generally between 20KHZ and 100KHZ).

   6. If there is no PWM wave output, replace the timing component C5, R8, C6 or UC3844. After the above steps are eliminated, the switching power supply should work normally.

      These six kinds are the method steps for the maintenance of the inverter switching power supply. Everyone must follow the certain method steps to eliminate the fault during the maintenance, so that the inverter switching power supply can be used normally.