1. Within three months, if the instrument fails to meet technical requirements due to its own reasons, it can be unconditionally replaced. 2. Free repair within one year, and lifelong maintenance and technical services. 3. If the instrument has quality issues, a repair plan will be proposed on the same day, and on-site handling will be conducted promptly. Alternative instruments can also be provided to meet user needs. 4. Free on-site technical support and training on instrument usage knowledge. 5. If the instrument malfunctions, please contact us promptly so that we can provide service. Appendix 1: Method for Replacing Paper in Panel Printer The printer equipped with the instrument has been installed with a paper roll at the factory. When the paper roll inside the printer is used up, a new paper roll needs to be installed. The specific installation process is as follows: (1) Remove the front cover of the printer. (2) Remove the entire printer from the instrument panel. Use your fingers to press the movable tabs on both sides of the printer inward, and gently take the entire printer off the instrument panel. Note: Before removing the printer, make sure to confirm that the printer power has been turned off. (3) Remove the paper roll shaft from the printer. (4) Slide the new paper roll onto the paper roll shaft, and install the paper roll shaft into the guide groove of the printer so that it will not fall out. (5) Cut the paper head into a cone shape. (6) Turn on the printer power, press the SEL key to turn off the SEL indicator light, then press the LF key to rotate the print head. At this time, use your hand to feed the paper head into the paper inlet below the print head, and the paper will quickly enter the print head until it emerges from the front of the print head. The exposed part should have a certain length. Press the SEL or LF key again to stop paper feeding. Turn off the power, close the front cover of the printer, and thread the paper head out through the outlet on the front cover. (7) Install the entire printer back onto the instrument panel. Usage Method of DC Resistance Tester: A: DC Power Test: Close the main power switch, the corresponding indicator light will turn on. Press the "Start/Stop" key to conduct the test. After the test, press the "Reset" key, and the instrument will display "Discharging". Wait until the instrument returns to the startup interface, then turn off the main power switch, and the corresponding indicator light will turn off. Then switch the test clips for another test. B: AC Power Test: Connect the AC 220V power supply, the "Charging" indicator light will turn on. Close the main power switch, and the corresponding indicator light will turn on. The test method is similar to the DC test. Special Attention: After the test, you must press the "Reset" key and wait until the instrument returns to the startup interface before turning off the power for the next test.