Teach you how to check and prevent PCB short circuit?

Electronic products repair encountered one of the most problem is the short circuit, short circuit to PCBA damage caused by large, small to burn to PCBA components, scrap. We only try to avoid short circuit, must grasp the production of each step, not every possible point inspection.


(1) if manual welding, to develop good habits, first of all, to visually check PCB plate welding, and using a multimeter to check the key circuit (especially the power and ground) is short; secondly, it using a multimeter to check whether the welding power and short time after a chip; in addition, don't throw the welding iron, if the solder flung to the leg of the chip (especially surface mount components), it is not easy to find.


(2) in the computer to open the PCB diagram, light circuit network, see what place away from the nearest, most likely to be attached to a piece of. Special attention should be paid to the IC internal short circuit.


(3) were found to have short circuit phenomenon. Take a piece of plate to the secant (particularly suitable for single / double plate secant will each part function blocks are energized, a portion of exclusion.


(4) using the short position analyzer, such as: Singapore PROTEQ CB2000 short trackers, euro RSCG Hongkong technology for short circuit to QT50 tracker, the British POLAR ToneOhm950 multilayer board short circuit detector etc..


(5) small size surface mount capacitor welding must be careful, especially the power supply filter capacitor (103 or 104), the number of many, very easy to cause the power supply and ground short circuit. Of course, sometimes bad luck, will meet the capacitor itself is short, so the best way is the capacitance detection again first before welding.


(6) if the BGA chip, the chip is covered all solder joints is invisible, but it is multilayer (more than 4), so it is best to design the power per chip split open, connected with magnetic beads or 0 ohm resistor, so that power and short circuit, open magnetic detection, easily position a chip. Because the BGA welding is difficult, if not the machine automatic welding, little attention will turn two solder ball short adjacent power and ground.