1、 Open the PCB design diagram on the computer, light up the short circuited network, and see where it is close and connected together. Pay special attention to short circuits inside the IC.

2、 If it is manual welding, good habits should be developed:

1. Before welding, visually inspect the PCB board and use a multimeter to check if critical circuits (especially power and ground) are short circuited;

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

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

3、 Discovered a short circuit phenomenon. Take a board to cut the line (especially suitable for single/double-layer boards), and after cutting, power on each functional block separately and gradually clean it.

4、 Using short-circuit positioning analysis instruments

5、 If there is a BGA chip, all solder joints are covered by the chip and cannot be seen, and it is a multi-layer board (4 layers or more), so the power supply of each chip is separated in the design and connected with magnetic beads or 0 ohm resistors. In this way, when a short circuit occurs between the power supply and ground, the magnetic bead detection is disconnected, and it is easy to locate a certain chip. Due to the difficulty of BGA soldering, if it is not actively soldered by the machine, a slight negligence can short-circuit the adjacent power and ground solder balls.

6、 Be careful when welding small-scale surface mount capacitors, especially power filter capacitors (103 or 104), which have a large quantity and can easily cause a short circuit between the power supply and ground. Of course, sometimes fate is not good and the capacitor itself may be short circuited. The method is to test the capacitor before welding.

Article source: Jiangmen single-sided and double-sided circuit boardhttp://www.yonghongpcb.com/