1. If it is manual soldering, it is necessary to develop a good habit.
First, visually check the PCB circuit board before soldering. And use a multimeter to check whether the key circuits (especially the power supply and the ground) are short-circuited;
secondly, after each soldering a main IC, use a multimeter to test whether the power supply and the ground are short-circuited; in addition, do not throw the soldering iron randomly when soldering. If solder was thrown onto the solder pins of the chip (especially surface mount components), it is not easy to find.
2. Open the PCB diagram on the computer, light up the short-circuited network, and see where it is closest and most easily connected. Pay special attention to the short circuit inside the IC.
3. If a short circuit is found. Take a board to cut the line (especially suitable for single/double board), after cutting the line, cut each part of the working blocks and energized separately, and exclude each parts step by step.
4. Using a Short Circuit Locator
5. If there is a BGA chip, solder joints cannot be seen because all the solder joints are covered by the chip, and it is usually a multi-layer board (4 layers or more), so it is best to separate the power supply of each chip when designing, and connect it with magnetic beads or 0 ohm resistors, so that
when there is a short circuit between the power supply and the ground, the magnetic bead is disconnected, and it is easy to locate a certain chip.
Due to the difficulty of BGA soldering, if it is not automatically soldered by the machine, it will easily short-circuit the two adjacent power supply and ground solder balls if you are not careful.
6. Be careful when soldering small-sized surface mount capacitors, especially the power filter capacitors (103 or 104). It is easy to cause a short circuit between the power supply and the ground. Of course, sometimes with bad luck, the capacitor itself is short-circuited, so the best way is to test the capacitors before soldering.