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In the iphone standby circuit, battery power supply, main power supply, BOOST power supply,

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and power supply converted by other chips,

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when we connect the battery or the adjustable power supply,

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they will all have voltage

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If the capacitor or chip connected to the line is damaged, it will cause a large current

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Next, we ground the capacitor on the line to simulate the

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damage of the components connected to the line,

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and look at the fault phenomenon

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We short-circuit the capacitor C2117

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that supplies power at the positive pole of the battery,

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let's see if there will be a large current

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Let's take a look at a good mainboard first

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After the good mainboard is connected to the power cord, the current does not jump

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until we trigger the switch

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Now, let's start to short-circuit the capacitor C2117

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We see that the voltage is pulled down

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and the current reaches around 5A

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It proves that component damage on the battery side can also lead to large current

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We short-circuit the capacitor C2611 of the main power supply line

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to see if there will be a large current

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Now, let's start to short-circuit the capacitor C2611

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We can see that the voltage has become 2.5V,

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and the current reaches about 5A

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It means that a short circuit of the main power supply will also cause a large current

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We short-circuit the capacitor C2303 in the boost

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power supply line to see if there will be a large current

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Now, let's start to short-circuit the capacitor C2303

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We see that this current is about 600mA

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It means that the short circuit of the boost power supply will also cause a large current,

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but the current does not exceed 1A

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For other conversion circuits, we will use the audio amplifier to demonstrate

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We short-circuit the audio amplifier C3431 to see if there will be a large current

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Now, let's start to short-circuit the capacitor C3431

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The audio amplifier conversion circuit will also cause a large current

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after a short circuit

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The voltage becomes 3.7V and the current reaches 5A