What should I do if I encounter a short circuit on the PCB circuit board? Today, the smt processing plant will explain to you some common problems in detail.
1. If it is manual soldering, develop a good habit. First, check the PCB board visually before soldering, and use a multimeter to check whether the key circuits (especially the power supply and ground) are short-circuited; secondly, each time a chip is soldered Use a multimeter to check whether the power supply and ground are short-circuited; in addition, do not throw the soldering iron randomly when soldering. If you throw the solder onto the solder feet 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 which place is closest to it, which is most likely to be connected. Pay special attention to the short circuit inside the IC.
3. A short circuit is found. Take a board to cut the line (especially suitable for single/double-layer boards). After the line is cut, each part of the functional block is energized separately, and some are eliminated.
4. 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 (above 4 layers), it is best to separate the power supply of each chip during the design, using magnetic beads or 0 ohms Resistor connection, so that when there is a short circuit between the power supply and the ground, the magnetic bead detection is disconnected, and it is easy to locate a certain chip. Because the welding of BGA is difficult, if it is not automatic welding by the machine, a little carelessness will short-circuit the adjacent power supply and the ground two solder balls.
5. Be careful when welding small-size surface-mount capacitors, especially power supply filter capacitors, which are large in number, which can easily 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 capacitor before welding.