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We will continue to talk about the maintenance of electrical leakage in this lesson

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The electrical leakage fault is directly related to the line of the battery positive pole

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and the line of the main power supply

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We learned the maintenance method of water ingress corrosion on the main power supply line before,

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and most of the electrical leakage is caused by water ingress corrosion

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How should we repair the mainboard if there is no water corrosion on the mainboard?

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In this case, some leakage may be relatively large,

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such as leakage of more than 100mA

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At this time, we can touch the components with our hands

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For example, we can touch the components with the back of the finger

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to see where the heat is,

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because the back of the finger is more sensitive

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The current needs to be above 100 mA,

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and we can sense the temperature by touching it with our fingers

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We power up the mainboard, and after two or three seconds we can touch

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Find the component that generates heat,

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we remove this component, which is usually either a capacitor or a chip

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After removing the components,

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we power up the mainboard again to see if there is any leakage

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If there is no more leakage, the fault will disappear

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This is the temperature perception method, also called temperature sense method

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In fact, the electrical leakage is generally more than 30 mA,

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and the fault point can be sensed by hand

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It depends on the individual, many people may not have very sensitive fingers

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This is the general repair method

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Then there is a more scientific way,

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which is to use thermal imaging equipment to find out the heat source

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Let me tell you the steps

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Power on the mainboard, turn on the thermal imager,

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and place the mainboard under the thermal imager

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It scans the temperature on the mainboard and presents the heating position on the display

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It is called an infrared PCB rapid diagnostic instrument,

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or an infrared temperature detector

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This kind of equipment is very helpful for our maintenance

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There are many styles of this device, let me show you

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The slogan says that it is a good partner for leakage maintenance,

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which can accurately capture small leakage below 5 mA

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and locate the leakage component in one second

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It generally sells for 1,800 to 3,000 more

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We search for mobile phone repair thermal imaging on Taobao,

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and we can see that there are many kinds

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For example, CPB infrared thermal imager,

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Potential third-generation infrared thermal imager

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After you buy, there will be a tutorial

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This device can quickly find heating components instead of temperature sensing method

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for faults with relatively small leakage currents

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After finding it, we can remove the components,

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or replace the components

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If it is a capacitor, there is no need to replace it after removing it

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If it is a chip, we can replace the chip

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Ok, that's it for this lesson