1、 Open the PCB design diagram on the computer, light up the short circuit network, and see where it is closer and easier to connect together. Pay special attention to internal short circuits in the IC.

2、 If it is manual welding, cultivate good habits:

1. Before welding, visually inspect the PCB board and use a multimeter to check for short circuits in key circuits (especially power and ground);

2. Every time a chip is soldered, use a multimeter to measure whether there is a short circuit between the power supply and ground;

3. When welding, do not throw the soldering iron randomly. If the solder is thrown onto the solder pins of the chip (especially surface mount components), it will be difficult to detect.

3、 A short circuit was found. Take a board to cut the thread (especially suitable for single/double layer boards), and after cutting, power on each functional block separately and gradually eliminate it.

4、 Use short-circuit positioning analysis instruments, such as:

Singapore PROTEQ CB2000 Short Circuit Tracker

Hong Kong Lingzhi Technology QT50 Short Circuit Tracker

UK POLAR ToneOhm950 multi-layer circuit short circuit detector

5、 If there is a BGA chip, since all solder joints are covered by the chip and cannot be seen, and it is a multi-layer board (more than 4 layers), it is better to separate the power supply of each chip during design and connect it with magnetic beads or 0 ohm resistors. This way, when there is a short circuit between the power supply and ground, the magnetic beads can be disconnected for detection, making it easy to locate a certain chip. Due to the difficulty of BGA welding, if it is not automatically welded by the machine, a slight carelessness may cause a short circuit between the adjacent power supply and the ground two solder balls.