Motherboard leakage and short circuit, so I repair（主板漏电和短路,我这样修）

Motherboard leakage and short circuit, so I repair（主板漏电和短路,我这样修） Motherboard leakage and short circuit, so I repair(主板漏 电和短路,我这样修) Motherboard leakage and short circuit, so I repair.Txt, if in ten million, I went to buy 30 sets of houses, rented to others, every day to collect the rent. Wow Kaka ~ ~ full horse is not necessarily the prince, may be Tang Seng; with wings are not angels, sometimes is a bird. Motherboard leakage and short circuit, so I repair First of all, I can not say that, as some methods say, the current is known as the IC, the capacitor, the inductance, or the resistance, the leakage, the short circuit, but so far there is no leakage that I can not find. And the leakage is divided into three cases, each has its own method: 1, small current leakage, regardless of size, the above power supply is not protected shall prevail. Leakage current of more than 100MA, usually obvious fever, we can go to touch, to find heating elements. If the heat is not too obvious, may be appropriate to increase the voltage, but for the sake of safety voltage should be controlled within 8V, the current should be less than 200MA; if the leakage current is too small, high voltage to 8V still had no fever, it can only remove the power and CPU power amplifier are taken off even when necessary, continue to increase a voltage to current up to 200MA, you can easily find the heating element. Here are three points to explain: (1) why is it necessary to remove the CPU? Remove the power and power amplifier to understand that the voltage is high and easy to damage, but the CPU is powered by the power supply and the power is taken. Is it still bad? The answer is yes, CPU is not as we think so simple, there are no published data, we have no way of knowing, in the case of MTK, the power supply under normal and remove the CPU boot when no current, which illustrates that there is a direct relationship between the CPU and the power supply, besides you can try not to take CPU voltage whether it will bad, I have learned the lessons of this. (2) the heating element is not necessarily a fault element. For example, a power supply IC supplies power to the load, such as a short load, usually heating, the most important is the power supply IC. In this case, we can find the real fault point by substitution method and open circuit method. (3) sometimes, when the voltage is added, the current does not rise or fall. When the voltage is adjusted to the normal voltage, the leakage is much smaller. It is better to try a little more, often returned to normal voltage has no leakage, and this "burning machine Dafa" a little similar to yo. 2, large current leakage, that is, the power supply on the protection. In this case, we should first measure the leakage resistance (that is, positive and negative ends of resistance), if the resistance is not 0, even if only a few ou, we can also use the power touch method to find short circuit components. But then you have to adjust the power supply voltage to 0, power up, and then slowly increase the voltage, when the current rises to 200MA, it is easy to find hot spots. You can see it burning smoke, smoke components to find the line! 3, direct short-circuit, this can not touch the hand. Direct short circuit (for example, solder joints short circuit), at this time, the resistance value is 0, the current is too big, will not heat up, we can only use open cut method to rule out. One is to take the possible component to test (if you know how to disconnect the component from the B+ and not to take it down), the biggest possibility is MP3 amplification of the IC, followed by power and power amplifiers. Of course, circuit maintenance experts will have more ways to find it, this is not discussed here. Finally to add, some models (such as part of the M machine) with power supply itself there will be leakage, this is not the correct access line caused by the battery type, we should judge it in the end there is no such connection leakage may be: from the battery contacts leads to negative, then the electric Chi Zhengji posted a piece of paper then, the battery power supply through the leads to positive and negative to the mobile phone power supply, it is very clear..... (1) can be divided into direct leakage and load leakage, leakage is directly connected directly to the battery element in normal voltage leakage, if the burning machine without reflection, can add a voltage higher than 5V above the burning, but because of some models is connected with the battery level too many elements, if you remove trouble. Don't dismantle it without reflection with the said voltage about 8V would be good also burned. If the risk of large machines, It is recommended that the IC, which is connected to the positive level of the battery, be removed in turn In addition, there are currently no separate CPU (not in IC power supply) is directly connected to battery, and CPU power supply is provided by the IC, I think that remove the power supply IC directly after burning can, without removing the CPU, of course, 220V would be another matter. If the load leakage refers to a IC power output to the way a load of IC leakage, disconnect the power supply and power supply mobile phone after checking all LDO (LDO) large capacitance of the output resistance (with two tubes are measured for common file, more than 1000, measured 300-500) can usually be determined it is a problem, then the voltage in the normal machine with resistance below 2.8 (starting from 0V) can cook for a while to find the damaged element. This method can not remove any parts. A little personal opinion, please correct me With the replacement method and open circuit method, no place to burn, B+ is directly to the ground, and this will not be hot, you try to power the positive and negative pinch on a tin above to see if it will burn. (voltage up to 0. PA, UEM, 5V) background lights, camera regulator are direct power supply battery. You put them in front of the inductor or destroyed protection tube, to see if there is no leakage. The smoke will melt rosin than with digital camera search cost much less do not believe also very effective. Try it!!!!!! with high power 0V slowly found no hot a negative pole is connected.