Switching power supply maintenance tips
The maintenance of switch mode power supply can be divided into two steps:
Cut off, "look, smell, ask, measure"
Look: Open the casing of the power supply, check if the fuse is blown, and then observe the internal condition of the power supply. If there are burnt areas or broken components on the PCB board of the power supply, focus on checking the components and related circuit components at this location. asset management
Wen: Smell the inside of the power supply for any burnt smell and check for burnt components.
Question: May I ask about the process of the power supply damage and whether any unauthorized operations were carried out on the power supply.
Quantity: Before powering on, use a multimeter to measure the voltage across the high voltage capacitor. If the fault is caused by the failure of the switch power supply to vibrate or the open circuit of the switch tube, in most cases, the voltage across the high-voltage filter capacitor has not been discharged. This voltage is over 300 volts and requires caution. Measure the forward and reverse resistance at both ends of the AC power cord and the charging status of the capacitor with a multimeter. The resistance value should not be too low, otherwise there may be a short circuit inside the power supply. Capacitors should be able to charge and discharge. Disconnect the load and measure the ground resistance of each output terminal separately. Under normal conditions, the meter needle should have capacitor charging and discharging oscillation, and the value indicated after * should be the resistance value of the discharge resistor of the circuit.
Power on detection
After powering on, observe whether the power supply has burnt fuses or individual components emitting smoke. If so, cut off the power supply in a timely manner for maintenance.
Measure whether there is a 300 volt output at both ends of the high-voltage filtering capacitor. If not, focus on checking the rectifier diode, filtering capacitor, etc.
