iPhone touch ID not working issue has been a sticky business for repair technicians for a
long time. What’s more, iPhone touch ID of iPhone 6 and later versions are bonded with
CPU, and Home Button replacing by users has a destructive effect on touch ID fingerprint
sensor function. The fact is that, about 80% of iPhone Touch ID failures are caused by
damaged home button flex. Well, this time REWA come up with a new solution regarding
to the damaged home button flex. Check it out by yourself now.
Restore iPhone Touch ID With Home Button Flex Reparing
Power on and test. “Unable to activate Touch ID on this iPhone”. Press Home Button, the returning function is normal.
Disassemble the phone and remove the display assembly. First of all, check the logic board connector J2118 for mouldy condition and dry Joint. Everything is fine.
Then, measure the resistance between J2118 and grounding. The value is also normal.
Take down the Home Touch Sensor Assembly and check the home button flex cable. There are obvious broken traces on the flex cable.
Preliminary judgment – Touch ID malfunction is caused by fractured flex cable circuit. We can fix the problem by replacing the fractured section with a new length of flex cable.
Pry up the back plate with Tweezer and Soldering Iron. Cut the fractured part from the flex cable with Sculpture Knife.
Scrape out the flex cable circuit. Be careful not to cut the circuit off.
Apply some BGA paste flux to the flex cable and then solder tins with Soldering Iron. Clean with PCB Cleaner after cooling.
Prepare a new Home Touch Sensor Assembly.
Pry up the back plate of the new Home Touch Sensor Assembly. Cut a length of flex cable from the new Home Touch Sensor Assembly (allow for some adjustment in length of the cut cable).
Fix the newly cut cable with double-sided adhesive. Then, scrape out the newly cut flex cable circuit. Be careful not to cut the circuit off.
Apply some BGA paste flux to the newly cut flex cable. Then solder tins with Soldering Iron. Clean with PCB Cleaner after cooling.
Cut out the excess parts of the newly cut flex cable. After that, apply 460 Glue to the bonding part and adhere the two cables carefully. Pay attention to the aligning position.
Once cables are fixed, apply some BGA paste flux and solder flex cables with Soldering Iron. Be careful with bridging and disturbed solder condition.
Clean with PCB Cleaner after cooling. Remember to check the circuit for bridging and disturbed solder.
Get the Home Touch Sensor Assembly mounted on the screen. Then buckle the display assembly to the logic board.
Power on and run Touch ID function test. Touch ID back to normal.
Take down the display assembly after test and take out the Home Touch Sensor Assembly. Prepare another length of cable. And then adhere the cable to the previous bonding part.
To further secure flex cables, solder with Soldering Iron. And then secure the back plate with Glue carefully.
Get the Home Touch Sensor Assembly mounted on the screen. Buckle the display assembly to the logic board. After that, power on and test. The phone works with normal Touch ID function.
For more details on restore iPhone Touch ID with Home Button flex repairing, please go to REWA YouTube channel.