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Step 3 of short sircuit repairing for iPhone standby circuit

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If we don't have a thermal imager,

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it can be repaired by following steps

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Here is the operation method

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After the mainboard is powered on,

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touch the mainboard with a hand to determine the hot position

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Smoke the rosin in the hot position, and then observe,

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where the rosin melts first, it means the component is damaged

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Avoid burning your hands when touching the mainboard

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Because after the component is damaged,

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the current will flow to the ground through the damaged component

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The greater the current, the more serious the damage to the components will be,

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and sometimes it can even reach more than 100 degrees

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Under the thermal imaging,

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the temperature of the short-circuit position of the mainboard reaches 140 degrees

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If your hand accidentally touches this position,

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you will definitely be burned

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So when touching the mainboard, do not press it with your hands

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In order to avoid burns,

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we can also limit the current of the adjustable power supply to 1A

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after that, we connect the mainboard to the adjustable power suppoly

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Then we can touch the mainboard

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At this time, the temperature of the hot position will not rise so high

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if the hot component is a charging tube, a charging chip,

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or a boost chip, we don't need to deal with it,

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because it may be caused by the short circuit of the rear stage

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Now, let me demonstrate

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After the mainboard is powered on,

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touch the mainboard with a hand to determine the hot position

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Disconnect the power and smoke the rosin in the hot position,

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We connect the mainboard to the adjustable power supply,

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and then observe whether the rosin on the components is melted

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if the hot component is a charging tube, a charging chip,

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or a boost chip, we don't need to deal with it,

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because it may be caused by the short circuit of the rear stage

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If the rosin on the chip or capacitor in other positions melts,

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it means that the chip or capacitor is damaged

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we need to replace it