For a newly designed circuit board, debugging often encounters some difficulties, especially when the PCB board is relatively large and there are many components, making it difficult to start. But if you master a reasonable set of debugging methods, debugging will be twice the result with half the effort. For newly retrieved PCB boards, we first need to roughly observe whether there are any problems on the PCB board, such as obvious cracks, short circuits, open circuits, etc. If necessary, check if the resistance between the power supply and the ground wire is large enough.

　　Then it's time to install the components. It is best not to install all modules that are independent of each other when you are not confident in ensuring their normal operation. Instead, you should install them part by part (for smaller circuits, you can install them all at once), which can easily determine the scope of the fault and avoid being unable to start when encountering problems. Generally speaking, the power supply can be installed first, and then powered on to check if the output voltage of the power supply is normal. If you are not confident when powering on (even if you are confident, it is recommended to add a fuse just in case), you can consider using an adjustable voltage regulator with current limiting function. First, preset the overcurrent protection current, then slowly increase the voltage value of the stabilized power supply, and monitor the input current, input voltage, and output voltage. If there are no overcurrent protection issues during the upward adjustment process, and the output voltage also reaches normal, it indicates that the power supply is OK. On the contrary, it is necessary to disconnect the power supply, find the fault point, and repeat the above steps until the power supply is normal.