1. Before maintenance, check if the power supply housing is properly grounded;

　　2. Measure if there is a voltage difference between the power supply housing and the operating table or workbench;

　　3. The aviation plug of the power input cannot be plugged incorrectly (old power supplies or main control boxes may have the same aviation plug, but their functions are different. Plugging in the wrong aviation plug may cause the internal control board to burn out or internal components to explode);

　　4. There are high voltages in many places inside the box. After powering on, do not touch the metal parts of the components with your hands;

　　5. The insulation of the measuring probes of measuring instruments (such as multimeters, oscilloscopes, etc.) and tools (such as wire cutters) should be checked for integrity;

　　6. When measuring voltage, confirm that the range is set to the voltage range. Ensure that the range of the instrument is greater than the voltage of the test point;

　　7. Before powering on, check if the load is connected or if the polarity is correct;

　　8. Before replacing components in the power supply box, turn off the power, then completely discharge the energy storage capacitor (using a 100Ω 50W power resistor), and confirm that there is no voltage with the voltage range before proceeding with the replacement or maintenance.

　　9. When replacing components in the power supply box or main control box, make a mark to ensure correct wiring during replacement. Pay special attention to this for components with polarity or high-current, high-power components. Otherwise, the components may burn out directly, and in severe cases, may explode;

　　10. After replacing the components, before powering on, measure the related components to check for short circuits (such as rectifier bridges, IGBT tubes, power supply input and output parts, power device input and output, etc.);

　　11. For machines that are unstable or work intermittently, check if the screws, terminals, etc. of the main circuit in the box are loose (may occur during transportation), if there is oxidation of the terminals, etc. Old power supplies or power supplies in poor environments should check for dust accumulation inside (can be blown away with an air gun); if there is a lot of oil stains inside the box and the service life is long, it cannot be repaired and should be scrapped.

　　12. During maintenance, for power supplies that customers request to be repaired, do not remove internal cable ties, control boards, cut wires, or make any unauthorized connections or modifications. This may cause interference or performance degradation to the entire machine. When returning, many old power supplies do not have wiring diagrams due to regulatory issues, which may greatly increase the difficulty of maintenance and in severe cases, lead to scrapping, affecting the reputation of the customer or company (Dazhu products are committed to lifelong maintenance).

　　13. For old power supplies that cannot be repaired on-site and need to be returned to the headquarters, all connection cables between the upper and lower boxes should be returned together for more comprehensive testing and maintenance.

　　14. Returned power supplies or main control boards should be protected against shock to prevent panel scratches, deformation, or component detachment, avoiding unnecessary losses for the company and causing trouble for maintenance work.

　　15. Returned power supplies or main control boards should be labeled with the detailed on-site fault of the power supply, the name of the office, etc., to facilitate analysis and maintenance by the maintenance technician. Sometimes, the fault phenomenon is inconsistent between testing on the entire machine and separate testing. Our maintenance personnel will make relevant maintenance records based on the label, track the maintenance of laser power supplies, and improve the repair yield.

　　16. For old semiconductor main control boxes or power supply boxes, when a fault is confirmed during maintenance and cannot be repaired on-site, the entire power supply or main control box should be returned. (Products are constantly being upgraded. For old versions that are more than two years old, the production line cannot repair and test scattered control boards or main control boards).

　　17. For power supplies that have been repaired multiple times but still cannot be used at the customer's site, the entire machine's wiring and other easily damaged parts should be checked on-site. Check the cause of the fault and make an on-site inspection record to return with the unit.