What to do if there is a short circuit on the PCB?

Short circuit of PCBA is what many engineers don't want to see. What should we do if there is a short circuit in the PCB? Today, follow China PCB manufacturer to see why there is a short circuit. If there is a short circuit, how do we troubleshoot it?

There are usually two short-circuit conditions. One is that the PCB circuit board has reached a certain service life. The second situation is that the inspection work in the production of PCB circuit boards is not good. However, these small errors in production have caused great harm to the entire PCB circuit board, which may lead to scrap. 

So how do we check and prevent short circuits on the circuit board?

First:

Open the PCB diagram on the computer, light up the short-circuited network, and see which place is closest to it and is most likely to be connected. Pay special attention to the IC internal short circuit.

Second:

Use short-circuit location analyzer, such as: Singapore PROTEQ CB2000 short-circuit tracker, Hong Kong Lingzhi Technology QT50 short-circuit tracker, British POLAR ToneOhm950 multi-layer circuit short-circuit detector, etc.

Third:

Be careful when soldering small size surface mount capacitors, especially power filter capacitors (103 or 104), which are large in number and easily cause a short circuit between the power supply and the ground. Of course, sometimes with bad luck, the capacitor itself is shorted, so the best way is to test the capacitor before soldering.

Fourth:

If it is manual soldering, develop a good habit. Firstly, visually check the PCB board before soldering, and use a multimeter to check whether the important circuits (especially power and ground) are short-circuited; secondly, after each chip is soldered, use a multimeter to measure whether the power and ground are short-circuited; in addition, do not throw the soldering iron at will during soldering . If solder tin is thrown on the solder leg of the chip (especially surface mount components), it is difficult to find it.

Fifth:

If there is a BGA chip, since all the solder joints are covered by the chip and cannot be seen, and it is a multi-layer board (above 4 layers), it is best to separate the power supply of each chip during the design and connect it with magnetic beads or 0 ohm resistors. In this way, when there is a short circuit between the power supply and the ground, it is easy to locate a certain chip by disconnecting the magnetic bead. Because the soldering of BGA is very difficult, if it is not automatically soldered by the machine, a little carelessness will short-circuit the adjacent power supply and the ground two solder balls.

Sixth:

If a short circuit is found, then take a board and cut the circuit (especially suitable for single-layer/double-layer boards). After cutting, energize each part of the function block and eliminate it part by part.

The above is the method we can do when there is a short circuit. Hope it will help you!