1. Open the PCB layout on the computer and light up the short circuit network to see where it is closest and the easiest one to connect to. Pay special attention to the short circuit inside the IC.
Second, if it is artificial welding, it is necessary to develop good habits:
1. Visually inspect PCB boards before welding, and use a multimeter to check if critical circuits (especially power and ground) are short-circuited;
2. Use a multimeter to test whether the power supply and the ground are short-circuited each time a chip is soldered.
3, do not throw the soldering iron when welding, if the solder is thrown to the chip foot (especially surface mount components), it is not easy to find.
Third, found a short circuit phenomenon. Take one board to cut the line (especially for single/double boards). After the secant, each section of the function block is energized and gradually removed.
Fourth, the use of short-circuit positioning analysis equipment
5. 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 (4 layers or more), it is better to split the power of each chip in the design, using magnetic beads or 0 ohms. Resistor connection, so that when the power supply and ground are short-circuited, the magnetic bead detection is broken and it is easy to locate a certain chip. Because BGA's welding is difficult, if it is not automatic welding of the machine, a little care will be taken to short circuit the adjacent power supply and the ground two solder balls.
Six, the small size of the surface mount capacitor must be careful when welding, especially the power filter capacitor (103 or 104), a large number, it is easy to cause a short circuit between the power supply and the ground. Of course, sometimes bad luck, you will encounter the capacitor itself is a short circuit, so the best way is to test the capacitance before welding.