1. Open the PCB design on the computer, light up the short-circuited network, and see where the nearest is,and where the easiest connect. Pay special attention to the short circuit inside the IC.
2. if it is manual welding, it is necessary to develop good habits:
A. Visually inspect the PCB board before soldering, and use a multimeter to check whether the important circuit (especially the power supply and ground) is short-circuited or not;
B. Use a multimeter to measure whether the power supply and ground are short-circuited after each chip is soldered.
C. Do not through off the soldering iron when soldering, if the solder tin is rubbed onto the soldering feet of the chip (especially surface mount components), it is not easy to find.
3. It was found that there was a short circuit. Take a board to cut the circuit (especially suitable for single/double board), after each secant, each part of the function block is energized separately and gradually eliminated.
4. Using the short-circuit positioning analysis instrument.
5. If there is a BGA chip, since all the solder joints are invisible by the chip cover, and it is a multi-layer pcb board (more than 4 layers), it is best to separate the power supply of each chip when designing, using magnetic beads or the resistor which is 0 ohms. so that the power supply is shorted to the ground, the magnetic bead is cut off and is detected and it is easy to locate a certain chip. Due to the difficulty in soldering the BGA, if it is not the machine’s automatic soldering, the adjacent power supply and ground solder balls will be short-circuited with a little care.
6. Small size surface mount capacitors must be careful when soldering, especially the power supply filter capacitor (103 or 104), the number is large, it is easy to cause the power supply and ground short circuit. Of course, sometimes the bad luck to come across the capacitor itself is short-circuited, so the best way is to check the capacitance before soldering.