Six inspection techniques for shorting PCB boards

First, open the PCB design on the computer, light the short-circuited network, and see where the nearest place is, the easiest to connect. Pay special attention to the short circuit inside the IC.

Second, if it is artificial welding, it is necessary to develop good habits:

1. Visually inspect the printed circuit board before soldering, and use a multimeter to check whether the critical circuit (especially the power supply and ground) is short-circuited;

2. Use a multimeter to measure whether the power supply and ground are short-circuited after each chip is soldered.

3. Do not smash the soldering iron when soldering the circuit board. If the solder is soldered to the soldering leg of the chip (especially the surface mount component), it is not easy to find.

Third, it was found that there was a short circuit. Take a board to cut the line (especially suitable for single/double board), after each secant, each part of the function block is energized separately and gradually eliminated.

Fourth, the use of 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 board (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. 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.

Sixth, 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 luck is not good, the capacitor itself is short-circuited, so the best way is to check the capacitance of the PCB before soldering.