Six PCB board short circuit inspection methods
First, turn on the PCB design on your computer, illuminate the shorted network, and view the nearest location, making it the easiest to connect. Pay special attention to the short circuit inside the IC.
Secondly, if it is artificial welding, it is necessary to develop good habits:
1. Visually inspect the PCB board before soldering, and use a multimeter to check whether the critical circuit (especially the power supply and grounding) is short-circuited;
2. When soldering the chip each time, use a multimeter to measure whether the power supply and grounding are short-circuited.
3. Do not rub the soldering iron when soldering. If the solder rubs on the solder fillet of the chip (especially surface mount components), it is not easy to find.
Third, a short circuit was found. Plate cutting lines (especially for single/double boards) are used. After each line is cut, each part of the function block is energized and gradually eliminated.
Fourth, the use of short-circuit positioning analyzer
Fifth，If there is a BGA chip, since all solder joints are not visible by the chip cover, and it is a multilayer board (more than 4 layers), it is better to separate the power of each chip. Designed to use magnetic beads or 0 ohms. The resistor is connected such that when the power supply is short-circuited to ground, the magnetic beads are detected and it is easy to position a certain chip. Since the BGA is difficult to solder, if it is not the automatic soldering of the machine, the adjacent power and ground balls will be carefully shorted.
Sixth, small size surface mount capacitors must be careful when soldering, especially the power supply filter capacitor (103 or 104), the large number, it is easy to cause power and ground short circuit. Of course, sometimes the luck is not good, the capacitor itself will be short-circuited, so the best way is to check the capacitor before soldering.