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In this lesson, we learn to find the hard disk power supply related to trigger protection in the bitmap

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We open Xinzhizao intelligent maintenance system,

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open the bitmap, circuit diagram, and component map of Xiaomi 10

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After we open the component map, we find this side,

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where the hard disk is written,

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and its location number is U5600, then it is the hard disk

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We switch to the circuit diagram,

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search for the U5600, and find the description of U5600

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We can see that it is the hard disk

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What are we looking for?

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We're looking for its power supply

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The power supply code starts with VCC, VDD or VREG

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What we see in this circuit is VREG_L17A_3P0,

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which is the 3V power supply of the hard disk

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Then the power supply below is VREG_L6A_1P2,

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which is a 1.2 volts power supply

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On this model, we see that it has two power supplies

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Then here, they are not power supplies,

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they are communication protocols, we have to find the power supply

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If the power supply circuit of the hard disk fails,

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it will lead to the trigger protection

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The hard disk we saw has two power supplies

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We switch to the bitmap, right-click,

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click to find the bitmap signal,

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and then it will automatically jump to the bitmap,

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We can directly see that U4200 is a power chip

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The 97th pin of the power chip VREG_L17A_3P0,

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this is the power output from the power supply

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These 4 capacitors are filter capacitors

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Then the purpose of this power supply is not to the filter capacitor,

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where does it go?

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then it needs to go to the hard disk chip U5600

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What is one thing we often do when we actually repair it?

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For example, if the hard disk has been touched by others,

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you can test whether the power supply of this hard disk is short-circuited

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You can use this method to measure its ground value on the capacitors,

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that is, use the diode gear to measure the ground value

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If the measured value is 0,

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it means that there is a short circuit in the power supply of the hard disk

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Switch back to the circuit diagram,

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this is the 3 volts power supply line,

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we double-click this power supply,

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then right-click, select this,

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and click to find the bitmap signal

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This power supply can be clearly displayed on the bitmap

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Let's see if it's powered, if it's what we're looking for

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It's the 12th pin output of the power supply

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Its name is VREG_L6A_1P2

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The source of this power supply is here, and it comes from here

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After the 3 filter capacitors,

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it is divided into two channels, one is to the hard disk,

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and the other is to the CPU

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It is the power supply of the hard disk and the power supply of the CPU

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This is another power supply for the hard disk, 1.2V power supply

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In the actual measurement,

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we have to judge the power supply of the hard disk,

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to test whether its voltage is normal,

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or whether it has a short circuit,

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how should we measure it, and where should we measure it?

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The method is the same as what I just said,

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we can find the capacitor,

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and set the multimeter to the diode gear

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The red test lead is connected to the ground wire,

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and the black test lead is connected to the capacitor

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Both ends of the capacitor can be used because they are all connected to one line

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When the ground value we measure is 0,

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it means that it is a short circuit

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When we measure a certain value, we don't care about it

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This is the way to find the power supply of the hard disk in the bitmap,

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and the judgment method

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Ok, that's it for this lesson