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iPhone startup high current

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In this video, we mainly explain the maintenance process of large current after startup

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The startup high current means that when the mainboard is energized,

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we trigger the switch, the current jumps from more than 100 or 200mA

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But some of it does not affect the boot,

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sometimes we call it power consumption fast failure

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Let's take a look at the repair process

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Maintenance process Step 1, appearance inspection

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The checks are the same

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Step 2 of the maintenance process

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After the mobile phone is triggered, the current is more than 200 mA

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If it turns on, we can test the phone's function to determine which circuit is responsible

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Common functions that lead to high startup current include fingerprint,

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photosensitivity, sensing,

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compass, and peripheral circuits such as USB

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Now let's test the sensitivity

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Sensitivity means that the screen automatically brightens when exposed to bright light

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Sensing distance is when we make a call,

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the screen will automatically turn off when there is an object near the receiver position

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If it doesn't turn off, there is a problem with sensing

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Let's open the compass and see if it rotates

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If it does not rotate, there is a problem with the compass circuit

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Measure which function is abnormal,

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we can overhaul the corresponding functional circuit

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Maintenance process Step 3

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If all the functions of the mobile phone are normal when tested,

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we can disconnect the cable and test the board again

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When the mainboard is powered up,

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we use a tweezer to trigger the switch pin,

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and we can see that the current starts to jump from 60mA

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So this is a normal mainboard

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Some external device damage will also lead to a larger startup current

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If we pull out the cables and run the power test, the boot current is normal

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We can buckle the cable in turn,

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determine which external device causes the fault

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Ok, that's it for this lesson