Common PCB circuit board failures are mainly concentrated on components, such as capacitors, resistors, inductors, diodes, triodes, field effect tubes, etc. The integrated chips and crystal oscillators are obviously damaged, and the more intuitive way to judge the failures of these components can be through Eyes to observe. There are obvious burn marks on the surface of the electronic components that are obviously damaged. Such failures can be solved by directly replacing the problematic components with new ones.
Of course, not all electronic component damage can be observed with the naked eye, such as the resistors, capacitors, diodes, etc. mentioned above. In some cases, the damage cannot be seen from the surface, and it needs to be repaired with professional inspection tools. Commonly used inspections include: multimeters, capacitance meters, etc., when the voltage or current of a certain electronic component is detected to be out of the normal range, it indicates that there is a problem with the component or the previous component. Replace it directly and check to see if it is normal.
If the component is broken, it can be detected whether it is observed with eyes or detected with an instrument, but sometimes when we give the components on the PCB board, we will encounter problems that cannot be detected, but the circuit board does not work properly. Case. Many novices encounter this kind of problem and have no choice but to make a new board or buy one. In fact, in this situation, in many cases, the performance of the components may be unstable due to the coordinated work of the components during the installation process.
In this case, the instrument is no longer helpful. You can try to judge the possible range of the fault based on the current and voltage, and try to reduce it as much as possible. An experienced engineer may be able to quickly determine the fault area, but which of the specific components is broken But it is not 100% sure. The only way is to try to replace the suspicious component until the problem component is found.