How to Fix iPhone 6 Screen Flicker Problem - Hardware Solution

Some iPhone users complained that the iPhone 6 screen keeps flickering. After turning on the power of the phone, the phone can be turned on but some flashing lines appear on the screen. This problem still exists after restarting the iPhone. What is going on here? We guess that there may be a problem with the hardware of the phone, we will open the iPhone 6 and test.

First, try to fix it by replacing new iPhone display assembly.

Turn off the iPhone 6, remove the SIM card. Use screwdrivers to remove the screws next to the iPhone lightning port, and then put iPhone on the CP320 Screen Heating Pad, after heat it for a while, we can use sucker to open the iPhone screen, and then carefully remove the iPhone display screen.

How to Fix iPhone 6 Screen Flicker Problem - Hardware
Now, install the new iPhone display assembly with opposite steps, when installation is done, turn on the iPhone 6, but the screen is still flickering. Now we confirmed that it's not the problem of the screen. We need to check iPhone motherboard.

As we know, the touch disease of iPhone is usually caused by iPhone touchscreen controller IC and the touchscreen processor IC, so, disassemble the iPhone again, and then take out the iPhone motherboard.

Use digital multimeter to measure the power supply voltage of PN5V7_SAGE_AVDDN, PP5V7_SAGE_AVDDH, PP5V1_GRAPE_VDDH, PP1V8_GRAPE on touchscreen controller IC and touchscreen processor IC, all the voltage measured are normal.

Measuring the diode data between touchscreen connector and U2402 with Fluke 17B+ Digital Multimeter, the data measured is normal.

How to Fix iPhone 6 Screen Flicker Problem - Hardware
Next we measure the diode data between the coupling capacitors of iPhone touch screen control IC U2401 and touchscreen processor U2402, the data measured is normal too.

All data measured are normal, so what's the real problem? Is it the problem of the replacement touchscreen ICs itself? We need to keep testing it.

As we know, the touch disease could be caused by touch screen control IC, and then causes iPhone touch screen totally not working. The damaged touch screen processor IC will cause the iPhone touch screen partially or randomly unresponsive. So, we suspect the iPhone touch processor is damaged.

Use QUICK 861DW Soldering Station to heat the iPhone touch processor, remove it with tweezers, and then install the new one. After installation, test the iPhone 6 again, but the problem still there.

How to Fix iPhone 6 Screen Flicker Problem - Hardware
According to our repair experience, the interference of a certain high-frequency signal also will cause this problem. Check iPhone schematic diagram via WUXINJI Dongle, we suspect the NFC chip, because the NFC chip is next to touchscreen processor, and the high-frequency signals it output can interrupt the normal working conditions of touchscreen ICs.

Now, we are going to replace the NFC IC. With the help of the QUICK 861DW hot air rework station and tweezers, we remove the NFC IC smoothly, and then install the new NFC IC.

After replacement, assemble the iPhone 6, and test it, now the iPhone screen works perfectly. Continue to test other functions on iPhone, all works properly.

If you have other issues with your Apple iPhone 6, please leave a message in the comments. We are always willing to help.

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