PCBA Tech - About PCBA repair in SMT patch processing

The maintenance technology in the general patch processing plant will perform the following operations.

1. Check the components

When the products in the SMT chip processing plant need to be repaired, the first thing to do is to determine whether the components of each solder joint have errors, omissions, and reverses. Confirming the authenticity of no materials is also a situation that needs to be considered. In view of Jingbang Electronics Chips imported from Sweden were pitted in 2011, so the supply of European and American countries may not be better than Huaqiangbei. If the problems of error, leakage, reverse and authenticity are eliminated, you can get a faulty circuit board. First check whether the circuit board is intact, whether each component is obviously burned out and whether it is plugged in.

2. Analysis of welding status

Basically 80% of the defects of the circuit board are the defects of the solder joints. Whether the solder joints are full and whether there are abnormalities, first of all, please refer to the management standards of the ISO9001 quality system and various SMT processing and welding quality standards to check whether there is any Visual defects such as false welding, false welding, short circuit, and whether the copper skin is obviously lifted. If there are any defective points of this product, repair them, if not, proceed to the next step.

3. Detection of component orientation

In the process of this link, we have basically eliminated some defects that can be seen with the naked eye. Now we still need to carefully check the diodes, electrolytic capacitors, the most used components on the circuit board, and other regulations on the direction, or positive Whether the components required by the negative pole are inserted in the wrong direction.

4. Tool inspection of components

If all the visual judgments are no problem, we need to borrow some auxiliary tools at this time. The most commonly used in SMT patch processing plants is to use a multimeter to simply measure our resistance, capacitance, transistor and other components, with a multimeter. The most important thing to check is to check whether the resistance values of these components are not up to the normal value, become larger or smaller, whether the capacitance is open, whether the inductance is open, and so on.

5. Power-on test

After all the above processes are completed, the conventional problems of the components can basically be eliminated, and there will be no ablation damage to the circuit board due to short circuits or bridges when the power is turned on. You can turn on the power and check whether the corresponding functions of the circuit board are normal. Basically, after all the processes are over, the customer’s BOM and Gerber, PCB schematic diagrams, etc. can be eliminated to judge and repair the defects of the customer’s products. The technicians in our maintenance department in the processing plant are all professional players carefully selected from the workshop.