When a computer breaks down, some clues are usually found. In general, fault inspection and diagnosis should follow the following principles:

1. Check the external parts first, then the internal parts.

For the failure of the host computer or display, first check whether the switch, fuse and socket outside the machine are open or short-circuited, and then open the case or display for inspection after confirming that the components outside the machine are normal. After opening the chassis, first observe whether the plug and socket of the system board are skewed, whether the resistor and capacitor pins collide, whether the surface is burnt, whether the chip surface is cracked, and whether the copper foil on the motherboard is burnt out; Also check whether there is a short circuit caused by foreign objects falling into the components of the motherboard, or whether there is a burnt and discolored place on the board, whether the wiring (copper foil) on the printed circuit board is broken, and so on.

In addition, pay attention to whether the main engine and the board have burnt smell, which is convenient for finding the fault and determining the short circuit position. At the same time, it is also necessary to monitor whether the working sound of power supply fan, soft/hard disk motor or seek mechanism, display transformer and other equipment is normal. In addition, the short-circuit fault of the system is often accompanied by abnormal sound, and monitoring can find some hidden dangers in time, which is helpful to take timely measures when accidents occur.