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In this lesson, we will talk about the maintenance of the OLED screen not displaying

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We have analyzed the situation that the power supply has an infinite value to the ground

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Next, let's take a look at the short circuit of the screen power supply to the ground value

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If there is a short circuit in the power supply,

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that is, when we measure its ground value, the value is not 553

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So what kind of state does the short circuit show?

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It shows 0

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There is a short circuit to ground, what is the reason?

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We only consider components with one end connected to this line and one end grounded,

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that is to say, which component is connected to this line at one end

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For example, if it is the ELVDD line,

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we measure that it is short-circuited

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This C6508 has one end connected to this line and the other end is grounded

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We must suspect this component

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For example, this ELVDD, how to analyze the short circuit we measure

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Take off this C6508 first, its line is connected to L6404 in series,

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we do not consider this component,

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because it is not grounded at both ends

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Although the L6404 is connected to this line, the other end is not grounded

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This inductor C6423 will be regarded as a wire at this time

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It is grounded at one end and connected to this line at the other end

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C6424 is also grounded at one end and connected to this line at one end

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including the chip U6401 is also connected to this ELVDD at one end

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So what components should we consider?

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U6401, C6424, C6423, and C6508

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We can remove these capacitors first,

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and measure again after removing them

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If the ground value is restored, the fault will be fixed

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If we only remove one capacitor, we don't need to replace it

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If it is still not enough to remove this capacitor,

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it will be better after removing 3 capacitors at last

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These capacitors can be added to it

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Make sure that there are at least two capacitors in this line

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If all 3 capacitors are taken out and it is still shorted,

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at this time we have to remove the chip

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Because there are three capacitors plus a chip in this circuit,

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it is generally a chip problem

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Remove the chip, reinstall it and measure again,

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if it is not shorted, the fault will be fixed

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If the chip is reinstalled and it still has a short circuit, then replace the chip

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This is an example of how to repair ELVDD short circuit

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Okay, that's it for this lesson