PCB circuit board short-circuit is the most common problem, there are generally two cases of short-circuit, one is PCB circuit board has reached a certain service life. The second case is the PCB circuit board production inspection is not in place. However, these small mistakes in production, the whole PCB circuit board is a great harm, it is likely to cause scrap.
1, found that there is a short-circuit phenomenon. The utility model takes a plate to cut the line, and is especially suitable for the single and double layer plates to cut each part of the functional blocks into power after the secant, and a part and a part are excluded.
2, small size table capacitor, welding must be careful, especially the power filter capacitor, a large number of, it is easy to cause power and ground short circuit. Of course, sometimes, if luck is bad, the capacitor itself is short circuited, so the best way is to check the capacitor before welding.
3, if it is artificial welding, to develop good habits.
First of all, to visually check PCB plates before welding, and use a multimeter to check the key circuit (especially for power and ground) is short circuited; use multimeter check whether each welding power supply and short-circuit a chip welding; don't throw the iron, if the solder thrown to the welding foot chip the (especially the SMD), it is not easy to find.
4, on the computer to open the PCB diagram, lit short circuit network, see where the nearest, the most easily connected to a piece. Particular attention should be paid to the internal short-circuit of the IC.
5, using short circuit positioning analyzer, such as: CB2000 short-circuit tracking device, QT50 short tracking device, ToneOhm950 multilayer circuit, short-circuit detector.
6, if there is a BGA chip, the chip pads are all covered invisible, and it is the multilayer board, so the best in the design of the power of each chip is split and connected by magnetic beads or 0 ohm, such power and short circuit, open magnetic detection, easy positioning to a chip. Since the welding of BGA is difficult, if the machine is not automatic welding, and pay little attention, it will short-circuit the adjacent power supply and the ground two solder ball.
PCB circuit board inspection work can not be ignored, every step to do the inspection work, must be treated carefully, the production process can not miss any suspicious, this can reduce the rate of rework and scrap rate, to avoid unnecessary losses.