Common Fault Analysis of DC Stabilized Power Supply
(1) Inspection of regulated power supply
In order to prevent overload or short circuit, the DC stabilized power supply is generally connected to the input and output terminals of the power supply through a fuse, and then connected to the external circuit through the input and output terminals. First of all, you should check whether the fuse is blown or loose, whether the connection between the input and output columns and the fuse is reliable, whether the terminal is short-circuited or loose, etc. After the inspection, if there is no abnormality, open the shell of the DC stabilized power supply to check whether the internal components are damaged, such as whether the resistors, capacitors, diodes, transistors, etc. are burst, burnt, or moldy.
(2) Measure the rectified output voltage
There is a group of rectified output voltages that can be measured in the DC stabilized power supply. Measuring these rectified output voltages can help to judge various faults in the circuit. If the measured rectified output voltage value is abnormal, various faults will occur in the operation of the regulated power supply. therefore,
Measuring the rectified output voltage is a necessary step.
(3) Test the performance of electronic components
If the measured rectified output voltage is normal, but the output voltage is not stable, then there is a fault in the voltage stabilizing circuit. For this reason, it is necessary to test the performance of crystal devices such as adjustment tubes and amplifier tubes, and whether the capacitor is broken down. If any electronic components are found to be damaged or their performance degraded during this process, the damaged components must be replaced.
(4) Check the circuit operating point
If the rectified output voltage and the performance of electronic components are normal, you should further check whether the operating point of the circuit is normal, that is, check whether the transistor is working in the saturation region or cut-off region due to the high or low operating point, and cannot work normally. . Under normal circumstances, the transistor of the DC stabilized power supply works in the amplification area.
(5) Analysis of working circuit
If no problem is found in the previous steps, it may be caused by damage to other components in the circuit. At this time, it is necessary to carefully analyze the working principle of the DC regulated power supply according to the circuit schematic diagram, find out the cause of the failure, and find out the damaged components.
