1. If it is manual welding, to develop good habits, first of all, before welding to visual inspection over the PCB board, and use multimeter check key circuit (especially power and ground) is short; secondly, each welding finished a chip with Multimeter measuring about whether the power and ground short circuit; 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 on the computer to open the PCB diagram, lit a short circuit of the network, to see where the nearest, the most likely to be connected to a piece of. Particular attention should be paid to the IC internal short circuit.
3 found a short circuit phenomenon. Take a piece of board to secant (especially for single / double plate after each part of secant function blocks are energized, part of exclusion.
4. Use short position analyzer, such as Singapore PROTEQ CB2000 short-circuit tracker, Hong Kong Lingzhi technology QT50 short-circuit tracker, British polar ToneOhm950 multilayer board road short-circuit detector etc..
5 small size of the surface mount capacitors must be careful, especially the power filter capacitors (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.if the BGA chip, 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.