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iPhone 7 Black Screen Repair – Logic Board Solution
Oct 19th, 2017

iPhone 7 starts up with black screen or no display, yet the boot current is normal. Screen replacing also can not solve the problem. We can draw the conclusion that the logic
board backlight circuit broke down. REWA LAB offers a logic board solution regarding to
the iPhone 7 black screen issue.

iPhone 7 Black Screen Repair - Logic Board Solution

iPhone 7 Black Screen Repair – Logic Board Solution

Power key power up, the phone shows no response.

iPhone 7 Black Screen Repair - Logic Board Solution

Take apart the phone and disconnect the battery. Connect the phone with the DC Power Supply. Booting current displays normally, yet the phone goes with no display.

iPhone 7 Black Screen Repair - Logic Board Solution

Disconnect the power supply and detach the display assembly. Replace with a new display assembly. Connect the phone with the DC Power Supply and power up. The phone still goes with no display

iPhone 7 Black Screen Repair - Logic Board Solution

Preliminary judgment – backlight circuit of the logic board broke down

Take out the logic board. Test grounding resistance value of J4502 – normal value. Which shows that backlight circuit is also normal. Yet backlight signal is connected directly with backlight IC U3701.

iPhone 7 Black Screen Repair - Logic Board Solution

Preliminary judgment – backlight IC U3701 broke down

Apply some BGA Paste Flux, take down the backlight IC with Hot Air Gun at 320 degrees.

iPhone 7 Black Screen Repair - Logic Board Solution

Clean the tins with Soldering Iron and then clean again with PCB Cleaner

iPhone 7 Black Screen Repair - Logic Board Solution

Apply some BGA Paste Flux. Align the backlight IC to the right place and solder it with Hot Air Gun at 320 degrees.

iPhone 7 Black Screen Repair - Logic Board Solution

Once the logic board is cooling enough, clean it with PCB Cleaner.

iPhone 7 Black Screen Repair - Logic Board Solution

Assemble the phone and test. The phone boots normally with screen display—fault cleared

iPhone 7 Black Screen Repair - Logic Board Solution

For more details on iPhone 7 Black Screen Repair guide, please go to REWA YouTube channel.

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