How to Fix iPhone 6S Plus Backlight/Screen Half Black | Chip Level Repair

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Half black screen/backlight problem is common in iPhone 6 Plus, 6s Plus, 7 Plus and 8 Plus, because the backlight circuits of these models have two sets of boost circuits. One boost circuit control left half backlight and the other one control right half backlight. If one set is failed while the other is still working, half of the screen will become black. in this article we will share how to troubleshoot and fix iPhone 6S Plus backlight half black, hope you enjoy our sharing.

Step 1 Function Test

Buckle the motherboard with screen assembly, then supply power to the motherboard. When powering on, half of the screen gets black and the other half lights on normally. Take down the motherboard for further troubleshooting.

Step 2 Diagnosis

Use the multimeter to measure the display connector diode resistance, and the diode resistance of the display connector pin 6 is measured open circuit. Through circuit analysis, the reasons that can cause display connector pin 6 diode resistance open are: defective FL4211, defective backlight chip, motherboard circuit damage.

Step 3 Troubleshooting

The diode resistance of the FL4211 to backlight chip end is measured normal, the diode resistance of the FL4211 to the display connector end is measured open circuit. As the line connection between the FL4211 to the display connector pin 6 end is measured normal, therefore, we can tell the defective inductor FL4211 has caused the half black screen.

Step 4 Repairing

Use the hot air gun and tweezers to remove the defective inductor and install a new good inductor. Remember to clean up the motherboard with the PCB cleaner, then cool down for 5 minutes

Step 5 Final Check

Buckle the motherboard with a known-good screen assembly, and supply power to it. Boot up, the half black screen problem solved, repair completed.

Please refer to below detailed video:

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Tools and Materials Used in This Video:

Solder flux

Hot air gun

Microscope

Multimeter

Tweezers

PCB cleaner

Cleanroom wipes

Soldering iron

Rework station

DC Power Supply

Rosin

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