Visual inspection is to visually inspect or use some simple instruments, such as stereo microscopes, metallographic microscopes or even magnifying glasses to check the appearance of the PCB and find the defective parts. The visual inspection mainly checks the PCB contamination, corrosion, location of the blasting board, circuit wiring and the regularity of the failure

For some parts that cannot be visually inspected, as well as the inside of the through hole of the PCB and other internal defects, it is necessary to use an X-ray system to check. X-ray system is the use of different material thickness or different material density to image the different principles of X-ray moisture absorption or transmittance. This technique is used more to inspect defects inside PCBA solder joints, via internal defects, and the location of defective solder joints in high-density packaged BGA or CSP devices.

Microsection analysis is the process of obtaining the cross-sectional structure of a PCB through a series of means and steps such as sampling, inlaying, slicing, polishing, etching, and observation. Through microsection analysis, a wealth of information reflecting the microstructure of the PCB (through holes, plating, etc.) can be obtained, which provides a good basis for the next step of quality improvement. We refer to IPC's standard IPC-TM-650 2.1.1 and IPC-MS-810 procedures.