How to Fix iPhone 6 Plus Unstable Touch with Vertical Lines | Chip Level Repair

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Unstable touch happens quite many among iPhone 6 plus. We have an iPhone 6 plus from our customer, which has unstable touch even with screen replaced, so its touch issue linked to a faulty hardware component, like loose connections in the motherboard circuit, in this video, we will share how to troubleshoot and fix iPhone 6 plus unstable touch with vertical lines, hope you enjoy our sharing.

Step 1 Function Test

We received a defective motherboard from our customer. First, reassemble and test the motherboard, we found the touch function is unstable, from time to time, the touch doesn’t work when press the screen, and when press the motherboard, the screen is flickering with vertical lines.

Step 2 Diagnosis

Remove the motherboard and check on the motherboard display connector and touch connector under the microscope. We found neither shape deformation nor water damage. For further test, we need to take off the protection sticker.

At this point, we found some solder flux on the motherboard, proving the motherboard has been pre-repaired. There are some cracks on the corners of touch ICs U2402 and U2401, proving they have been replaced. Except defective touch IC, other reasons can cause the iPhone 6 plus unstable touch, flickering with vertical lines are touch power supply -5.7V voltage defect or poor contact on the touch sync signal line.

Step 3 Troubleshooting

As the -5.7V diode resistance of the capacitor C2409 is measured normal. We can therefore rule out the possibility of defective -5.7V power supply. Next, use the hot air gun to heat and remove the touch IC U2402, clean well, then scrape off the touch IC U2402 pin M1 contact point, and solder tin with soldering iron.

Add some solder flux and jumper the conductor cooper wire with soldering iron. You can apply some green PCB UV solder mask to prevent short circuit and use the UV glue curing lamp for about one-minute help to solidify. And finally add some more solder flux and install a new good touch IC U2402

Step 4 Reassemble & Test

Cool down for 5 minutes then install the motherboard and retest. Touch function gets back to normal, and there’s no screen flickering or vertical line when press the motherboard. Repair completed

Please refer to below detailed video:

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Questions are utterly welcome!

Tools and Materials Used in This Video:

Solder flux

Hot air gun

Microscope

Multimeter

Tweezers

PCB cleaner

Cleanroom wipes

Desoldering braid/solder wick

Rework station

Spudger

Soldering iron

Conductor cooper wire

Green PCB UV curable solder mask

UV glue curing lamp

Step 1 Function Test

We received a defective motherboard from our customer. First, reassemble and test the motherboard, we found the touch function is unstable, from time to time, the touch doesn’t work when press the screen, and when press the motherboard, the screen is flickering with vertical lines.

Step 2 Diagnosis

Remove the motherboard and check on the motherboard display connector and touch connector under the microscope. We found neither shape deformation nor water damage. For further test, we need to take off the protection sticker.

At this point, we found some solder flux on the motherboard, proving the motherboard has been pre-repaired. There are some cracks on the corners of touch ICs U2402 and U2401, proving they have been replaced. Except defective touch IC, other reasons can cause the iPhone 6 plus unstable touch, flickering with vertical lines are touch power supply -5.7V voltage defect or poor contact on the touch sync signal line.

Step 3 Troubleshooting

As the -5.7V diode resistance of the capacitor C2409 is measured normal. We can therefore rule out the possibility of defective -5.7V power supply. Next, use the hot air gun to heat and remove the touch IC U2402, clean well, then scrape off the touch IC U2402 pin M1 contact point, and solder tin with soldering iron.

Add some solder flux and jumper the conductor cooper wire with soldering iron. You can apply some green PCB UV solder mask to prevent short circuit and use the UV glue curing lamp for about one-minute help to solidify. And finally add some more solder flux and install a new good touch IC U2402

Step 4 Reassemble & Test

Cool down for 5 minutes then install the motherboard and retest. Touch function gets back to normal, and there’s no screen flickering or vertical line when press the motherboard. Repair completed

Please refer to below detailed video:

Connect with us

On FacebookLinkedInTwitterYouTubeInstagram

Questions are utterly welcome!

Tools and Materials Used in This Video:

Solder flux

Hot air gun

Microscope

Multimeter

Tweezers

PCB cleaner

Cleanroom wipes

Desoldering braid/solder wick

Rework station

Spudger

Soldering iron

Conductor cooper wire

Green PCB UV curable solder mask

UV glue curing lamp

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