PCB Tech - PCBA lecture hall: How to quickly repair circuit boards?

Making a PCB board is not a simple process to finish the board, just drill a hole and punch in the components. PCB production is not difficult, the difficulty lies in troubleshooting after the production is completed. Whether it is a personal hobbyist or an industrial engineer, it is also quite a headache for PCBA circuit boards to encounter problems when debugging, just like programmers encountering BUGs.

Some people have a strong interest in debugging PCBA circuit boards. Just like programmers solving BUGs, there are many common PCBA circuit board problems. Common problems are except for circuit board design, damage to electronic components, short circuits, and components. The quality of PCBA circuit board disconnection faults are not rare.

Common PCBA 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 the help of 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, directly replace it 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 they 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 can no longer help. You can try to judge the possible range of the fault according to 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. Last year, my laptop motherboard was flooded, and when I was repairing it to the master, I also encountered that it could not detect the fault, and during the repair process, I replaced three components, namely the power supply chip, diode, and USB charging component (that is, the blue notebook). The socket can be used to charge the device when it is turned off). In the end, the suspicious chip was replaced through a wave of detection and investigation, and it was finally determined that a component on the side of the South Bridge chip was short-circuited.

The above is actually the problem of electronic components. Of course, since the PCBA circuit board is the foothold of the components, then the circuit board failure must also exist. The simplest example is the dead tinned part. Due to the manufacturing process, In the process of PCB corrosion, disconnection may occur. In this case, if you can't make up the wire, you can only use a thin copper wire flying wire to solve it.

PCBA circuit board failure is indeed very troublesome when it is not obviously damaged. In the process of troubleshooting, there will be a spirit of concentration. After the problem is found, there will be an inexplicable sense of accomplishment. The programmer solves the BUG. In this mood, I often like to investigate some difficult-to-maintain boards. I think that is a kind of fun.