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How To Check And Avoid Short Circuit On PCB

Mar. 12, 2019

1. If it is artificial soldering, such as Green Solder Mask PCB. To develop good habits, 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. Secondly, use a multimeter to measure the power and ground each time one chip is soldered. Whether it is 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. Care must be taken when soldering small-sized surface-mount capacitors, especially power supply filter capacitors (103 or 104), which can easily cause short-circuit between power supply and ground. 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.

Green Solder Mask PCB

3. If there is a BGA chip, since all the solder joints are invisible by the chip cover, and it is a Multilayer PCB (more than 4 layers), it is best 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. Because the BGA is difficult to solder, 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.

4. Open the PCB on the computer, illuminate the short-circuited network, and see where it is closest to it, the easiest to connect. Pay special attention to the internal short circuit of the IC.

5. A short circuit was found. Take a board to cut the line (especially suitable for single/double board secant, each part of the function block is energized separately, part of which is excluded.

6. Use short-circuit positioning analyzer, such as: Singapore PROTEQ CB2000 short-circuit tracker, Hong Kong Lingzhi QT50 short-circuit tracker, UK POLAR ToneOhm950 multi-layer circuit short-circuit detector.