First, the computer to open the Double Layer PCB design, the short circuit of the network lit, to see what the nearest place, the most easily connected to a piece. Pay special attention to the short circuit inside the IC.
Second, if it is artificial welding, to develop good habits:
1, before welding to visually check again Double Layer PCB board, and check with a multimeter key circuits (especially power and ground) whether the short circuit;
2, each time a chip on the welding with a multimeter to measure the power and ground is short circuit;
3, when welding do not chaos rejection of iron, if the solder to the chip on the welding feet (especially the surface components), it is not easy to find.
Third, found a short circuit phenomenon. Double Layer PCB Take a board to secant (especially for single / double board), cut off after each part of the functional block were power, and gradually excluded.
Fourth, the use of short-circuit positioning analysis equipment
5, if there is a BGA chip, because all the solder joints are covered by the chip can not see, but also multi-layer board (4 or more), it is best in the design of each chip will be separated from the power, with beads or 0 Resistance connection, so that when the power and ground short circuit, Double Layer PCB disconnect the bead detection, it is easy to locate a chip. As the BGA welding is difficult, if not the machine automatically welding, a little attention will be adjacent to the power and the two short-circuit solder ball.
6, small size of the surface mount capacitor must be careful when welding, especially the power filter capacitor (103 or 104), the number of large, it is easy to cause power and ground short circuit. Of course, sometimes bad luck, will encounter the capacitor itself is short-circuit, Double Layer PCB so the best way is to weld the capacitor before the first test again.