Power supply board failures occur frequently in CAWS600B automatic weather stations, often resulting in data missing. Because manufacturers did not provide the power supply board circuit diagram, troubleshooting is difficult. In order to quickly repair the power supply board faults and improve troubleshooting efficiency, based on the observation and analysis of the power supply board and the realted data, a detailed circuit diagram is presented, and a brief introduction is made to the working principles of the CAWS600B automatic weather station power supply. The analysis concludes that the main causes for the damage of the power supply board are: long term high electric voltage, small rated bridge electric current (BD1 ), large rated current of the primary transformer air switch, and high temperature in the collector. Some specific suggestions for improvement are given for observers as reference in practical maintenance.