6 methods for short circuit detection of PCB boards
It is well known in the field of PCB circuit boards that it is indispensable to make a quality PCB board. Multi-directional detection and good detection to improve the efficiency of detection. The following are several methods for detecting a short circuit on a PCB board.
1. If it is artificial welding, it is necessary to develop a good habit. First, visually inspect the PCB board before soldering, and use a multimeter to check whether the critical circuit (especially the power supply and the ground) is short-circuited. Second, each time the chip is soldered. Use a multimeter to measure whether the power supply and ground are short-circuited. In addition, do not smash the soldering iron during soldering. If the solder is soldered to the soldering legs of the chip (especially surface-mount components), it is not easy to find.
2. Open the PCB diagram on the computer, illuminate the short-circuited network, and see where it is closest to it. It is most likely to be connected. Pay special attention to the internal short circuit of the IC.
3. Found a short circuit. Take a board to sew the line (especially for single/double board). After secant, each part of the function block is energized separately, and some parts are excluded.
4, the use of short-circuit positioning analyzer, such as: Singapore PROTEQCB2000 short-circuit tracker, Hong Kong Lingzhi Technology QT50 short-circuit tracker, the United Kingdom POLARToneOhm950 multi-layer circuit short-circuit detector.
5. If there is a BGA chip, since all the solder joints are invisible by the chip cover, and it is a multi-layer board (more than 4 layers), it is better to separate the power of each chip at the time of design, using magnetic beads or 0 ohms. The resistor is connected so that when the power supply is shorted to the ground, the magnetic bead 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 power and ground short circuit. Of course, sometimes the luck is not good, the capacitor itself is short-circuited, so the best way is to check the capacitance before soldering. PCB proofing