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Measure the SCLK voltage at the 2 Pin of the resistor R7753, the value is 3.3V, which it's normal. Measure the PWM Pin voltage at the 2 Pin of the resistor R7704, the value is 2.8V, which it's normal. Measure the EN Pin voltage at the 2 Pin of the resistor R7731, the value is 2.8V, which it's normal. Measure the VDDIO voltage through capacitor C7711, the value is 3.3V, which it's normal.

Measure the VIN voltage through capacitor C7710, the value is 5V, which it's normal. Open the schematic diagram to measure the working condition for the U7701. It is controlled by backlight chip U7701, use digital multimeter to measure the voltage for the boost inductor L7701 it's 8.5V, which means there's no boost to the voltage. Open the ZXW Dongle to check MacBook schematic diagram and bitmap to find the screen flex cable connector, and then check MacBook backlight power supply circuit.Īccording to the MacBook schematic diagram, we know that the PPHV_SOSW_LCDBKLT is the screen backlight power supply, check the source of the PPHV_SOSW_LCDBKLT. In order to repair the backlight circuit, it has to be connected to the screen, the MacBook motherboard has to recognize the screen, so the open signal will display smoothly.

Remove the top half of the MacBook (display screen part), and then connect the MacBook motherboard to the screen via screen flex cable. The model for this MacBook air is A1466, the motherboard model is 820-00165-A, and it’s released in 2015.ĭisassemble the MacBook Air, remove the rear case, and then remove the MacBook motherboard. After removing the MacBook Air screen problem, we need to check the motherboard. Press the power button on MacBook, the boot bell rang smoothly, after few seconds, we found the MacBook Air screen has no backlight, it's abnormal. Solution: MacBook Air No Backlight After booting (A1466)