Inspection method for short circuit of PCB circuit board
Release Time:2016-04-27 Source:Original Views:9507
1、 if it is manual welding, to develop good habits, first of all, before welding to visual inspection over the PCB board, and multimeter check key circuit (especially power and ground) is short; secondly, each welding finished a chip with Multimeter measuring about power and ground are short; in addition, welding not disorderly jilt iron. If the solder thrown on a chip welding foot (especially surface mount component), is not easy to find.
2、 open PCB map on the computer, the network of short circuit, to see what is the nearest, most likely to be connected to a piece of. Particular attention should be paid to the IC internal short circuit.
3、found that there is a short circuit phenomenon. Take a piece of plate to secant (particularly suitable for single / double plate), secant will each part function blocks are respectively energized, part of a part of exclusion.
4、 the use of short circuit position analyzer, such as Singapore PROTEQCB2000 short-circuit tracker, Hong Kong Lingzhi technology QT50 short-circuit tracker, the British POLARToneOhm950 multilayer board road short-circuit detector etc..
5、if there is a chip BGA, since all solder joints is chip covered invisible and multilayer (more than 4 layers), so it is best in the design of each chip of the power split open, connected by magnetic beads or 0 ohm resistor, so there power earthing and short circuit, disconnect the magnetic beads were used to detect, very easy to locate to a chip. As BGA welding is difficult, if not the machine automatic welding, a little attention will be adjacent to the power supply and the two short circuit.
6、the small size of the surface mount capacitors must be careful, especially the special power filter capacitor (103 or 104), a large number, it is easy to cause power supply and short circuit. Of course, sometimes bad luck, will encounter the capacitor itself is a short circuit, so the best way is to detect the capacitance before welding.