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iPhone backlight circuit repairing

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This video mainly explains the phenomenon of backlight circuit failure

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and the English meaning of common circuits

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Common faults in backlight circuits include light and dark screens and dark screens

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Light and dark screen means that after the mainboard is powered on,

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half of the screen is bright and half is black

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Dark screen means that the screen is black after the mainboard is powered on,

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but when the screen is illuminated by strong light,

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you can see images displayed inside the screen

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Like this is a dark screen failure

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Common terms meaning of backlight circuit

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In the backlight circuit, BL refers to backlight,

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and CAT refers to feedback or loop

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ANODE refers to the power supply of the backlight,

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or the positive pole of the backlight power supply

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For example, in the picture, pin 16 is backlight feedback 1

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Pin 18 is the backlight power supply,

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pin 20 is the backlight feedback 2

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Pins 16, 18, and 20 are a group of backlights, marked BL34

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Pins 22, 24, 26 are another group of backlights, marked BL12

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In the iPhone, the LCD screen will have a backlight circuit

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And there is only one set of backlight circuits for 4.7-inch screens,

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and two sets of backlight chips for 5.5-inch and above screens

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In the current picture, there are two sets of backlights

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Ok, that's it for this lesson