PCB Technical - ​Tips and methods to quickly find PCB board faults

Making PCB boards according to the craft is not a simple method. PCB production is not difficult because of the fault investigation after the production is completed. Individual hobbyists and industry engineers also encounter problems when debugging PCB circuit boards, just like programmers encounter errors.

Some people have a strong interest in debugging PCB circuit boards, just like programmers solving bugs. In addition to common problems such as circuit board design, electronic component damage, circuit short-circuit component quality, and PCB circuit board disconnection faults.

Damaged diode ring color resistance.

Common PCB circuit board failures are mainly concentrated on components, such as crystal oscillators of capacitors, resistors, inductance transistors. The intuitive method of judging the failure of these components can be seen by the eyes. There are obvious burn marks on the surface of electronic components. This failure can directly replace the problem component.

The Metaki that is suspected of damage is not the damage of this component.

Of course, not all electronic components can be observed with the naked eye, such as the resistors, capacitors, and diodes mentioned above. In some cases, it is impossible to see the damage from the surface. It is necessary to use professional inspection tools for common inspection tools: multimeters, capacitance meters, etc., to detect the normal range of voltage or current of electronic components. The result shows that there is a problem of direct replacement and inspection of the component or the front component to see if it is normal.

The appearance of the circuit board is not damaged, and the fault cannot be detected.

If the component is broken, both the eyes and the instrument can detect it, but sometimes when we use the component on the PCB board, we will not have a problem. But the circuit board does not work properly. Many novices have no choice but to make another plank or buy a plank. In fact, in this case, due to the coordination of various components, the performance of the component during installation may be unstable.

The circuit blocks of the circuit board are divided.

In this case, the instrument is no longer helpful and tries to narrow the scope of the fault as much as possible based on the current and voltage. Experienced engineers can quickly determine the fault area, but cannot be 100% sure that a specific component is bad. The only way is to change the suspicious component until the problem component is found. Last year, my laptop motherboard was repaired to the owner without any faults, and three parts were replaced during the repair process. Power supply chip diode USB charging element (that is, the notebook blue socket can charge the device when it is turned off). Finally, the suspicious chip was replaced through wave detection and investigation, and it was finally determined to be a short circuit of the components on the edge of the South Bridge chip.

The circuit board is flying.

Of course, because the PCB circuit board is the foothold of the component, the circuit board failure must exist. The simplest example is the disconnection of the tinned part during the PCB corrosion process due to the production process. In this case, if you cannot supplement the wires, you can only use thin copper wires.

PS: PCB circuit board failure is really troublesome, there is no obvious damage, there will be a focus during the investigation process. When you find a problem, there is an inexplicable sense of accomplishment. The programmer solved this problem. I often like to find wooden boards that are difficult to repair. I think this is very interesting.