Door Sensor Contact Toggle
Door sensor contact toggle
In general, a blown fuse indicates a problem with the internal wiring of the power supply. Since the power supply operates under a condition of high voltage and high current, the fluctuation and surge of the power grid voltage will cause the current in the power supply to increase instantaneously and cause the fuse to blow. Focus should be checked on the power input rectifier diode, high voltage filter electrolytic capacitor, inverter power switch, etc., check whether the breakdown of this component, open circuit, damage and so on. If it is indeed a fuse blow, you should first look at the various components on the circuit board, see whether the appearance of these components are burned, there is no electrolyte overflow, if you do not find the above situation, then use a multimeter to measure the switch with or without breakdown short circuit . Special attention should be paid to the fact that: When a component is found to be damaged, it must not be directly switched on after it is replaced. This is likely because other high-voltage components are still defective and the replaced component will be damaged. All high-voltage components of the above circuit must be fully implemented. After checking the measurement, the fuse blowout fault can be completely eliminated.
No DC voltage output or unstable voltage output
If the fuse is intact, the DC voltage at each stage has no output under load. This situation is mainly caused by the following reasons: open circuit, short circuit phenomenon in the power supply, overvoltage, overcurrent protection circuit failure, auxiliary power supply failure, oscillation circuit does not work, power load is heavy, rectifier diode in high-frequency rectifier filter circuit Breakdown, filter capacitor leakage and so on. After measuring the secondary components with a multimeter and eliminating high-frequency rectifier diode breakdown and load short-circuit conditions, if the output is zero at this time, the power supply's control circuit may have failed. If some of the voltage outputs indicate that the previous stage circuit is working properly, the fault is in the high-frequency rectifying filter circuit. The high-frequency filter circuit is mainly composed of a rectifier diode and a low-voltage filter capacitor to form a DC voltage output, in which the rectification diode breakdown will cause no voltage output of the circuit, and the filter capacitor leakage will cause the output voltage to be unstable and other faults. Use a multimeter to statically measure the corresponding component to check for damaged components.
Poor power supply capability
Poor power load capability is a common fault, and it usually occurs in old-style or long-time power supplies. The main reason is that each component is aging, the operation of the switch tube is not stable, and heat dissipation is not performed in time. Should focus on checking whether the zener diode heat leakage, rectifier diode damage, high-voltage filter capacitor damage.