Short circuit inspection method for PCB circuit boards
- Release on:2018-07-24
For electronic engineers, the fabrication of the board is an inevitable step, but the short circuit of the board is a relatively easy problem in the board manufacturing process. A short circuit may cause the component to burn out, causing the system to lose weight, so we must pay attention to it. So how do we check and prevent circuit board shorts?
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 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.
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. Use short circuit positioning analyzer
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.(printed circuit boards supplier)
6. Be careful when soldering small-sized surface-mount capacitors, especially the power supply filter capacitors, which are easy to 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.