The switching power supply has no output, and the fuse is normal
Fault: The switching power supply is not working or has entered a protection state.
First, measure whether the start-up pin of the power control chip has a start-up voltage. If there is no start-up voltage or the start-up voltage is too low, check whether the start-up resistor and the components connected to the start-up pin are leaking current. If the power control chip is normal, the above inspection Faults can be found quickly.
If there is a start-up voltage, measure whether the output of the control chip has high and low level jumps at the moment of power-on. If there is no jump, it means that the control chip is broken, the peripheral oscillation circuit components or the protection circuit have problems, and the control can be replaced first. Chip, and then check the peripheral compon
