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Tutorial: iPhone 7 Backlight Failure Repair


What are the characteristics of iPhone 7 backlight failure? According to our maintenance experience, we will encounter some common situations, such as iPhone touch screen does not show, the screen light is dim or can not adjust brightness. In this article, we will introduce how to repair iPhone 7 backlight failure step by step.


At first, we connect WUXINJI Dongle to check iPhone 7 backlight power supply schematic diagram. 

By reading the iPhone schematic diagram, we know that the iPhone backlight boost IC output three sets of backlight power supply signals, they were PP_LCM_BLANODE (16.5V Cathode Voltage), PP_LCM_BL_CAT1 and PP_LCM_BL_CAT2, these three circuit signals are sent to the display interface via three inductors respectively, the pictures as follows. 
 
The three inductors are easy to damage, and then cause iPhone to have no backlight or light instability, sometimes bright, but sometimes not bright. In this case, we can repair it through short connections.

If there is no backlight on iPhone 7, use the fluke 15B+ digital multimeter to measure the diode data of the PPYLCMCYBLYCAT1, PPYLCMYBLY anode (backlight anode power) and PPYLCMYBLYCAT2, and put it under the stereo zoom microscope to check the short connection on the three inductors, if their work is good, they It can be repaired by replacing the iPhone backlight to boost the IC.

Get more cell phone repair tutorials from www.vipfixphone.com

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