To determine whether an integrated circuit block is good or bad, use a multimeter to measure the working voltage, resistance to the ground, and working current of each pin of the integrated circuit block.
You can also remove the integrated block to measure whether the resistance between the pins of the integrated block and the ground pin is normal. At the same time, you can measure whether the ground resistance of the pins of the external circuit is normal when the integrated block is removed. In particular, when replacing integrated circuit blocks, we must pay attention to the welding quality and welding time.
Some integrated circuit blocks have more pins, such as improper welding is easy to produce new faults.
Welding time is too long, it is easy to damage the internal circuit of the integrated block, and even make the copper foil and substrate of its printed circuit separate from the increase of unnecessary work, it is best to use a special soldering iron head when welding, to speed up the welding time, and pay attention to heat dissipation.
If too many pins are not welded once, they can be welded again later.
Or buy back an integrated circuit socket with the same pin, weld the socket first, and then insert the integrated circuit block, it is best to do so. When replacing an IC block, it is generally required to replace it with an IC of the same model and specification. When the original model and original specifications of the integrated circuit can not be found, it can be considered to replace it with an integrated circuit block with similar functions, but it should be noted that the supply voltage, impedance matching, pin position and peripheral control circuit should be understood when replacing.
Generally now the motherboard bad power supply core is very likely, the power chip is broken, the CPU is generally no temperature, then you can use the diode file of the digital multimeter to measure the inductance and the ground on and off, if the multimeter is called a long resistance value, the power supply core is good, if the inductance to the ground short circuit, the motherboard power supply part is absolutely problematic, First take down the triode on the motherboard with several adjusting power supply, if the inductance is still short circuit, then the motherboard power core is absolutely broken! And adjust the power supply of the transistor is broken, the capacitor next to the transistor is generally broken (motherboard capacitor is good or bad detection that is too simple, just look at the line, the capacitor is broken, the absolute capacitor in the middle will definitely rise a small part). It should also be noted that: after replacing the parts of the power supply part of the motherboard, the voltage on the inductor must be measured between 1.5V-2.0V before installing the CPU!