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How to Repair iPhone 6S Fingerprint


We are going to fix iPhone 6S fingerprint failure. Check circuit diagram of iPhone 6S fingerprint line interface on WUXINJI Dongle, the difference with iPhone 6 is that the iPhone 6S has more circuit. The left of the fingerprint line interface circuit map is control signal of fingerprint; the right part is new function--Force Touch, also called pressure feeling control.
 


We get to know from schematic diagram that the power supply of fingerprint has 3 circuits, one is 1.8V, one is 3.0V and another one is 16.5V. If the 1.8V and 3.0V is abnormal, it cause fingerprint failed to turn on, these two voltages can be reached to fingerprint interface when you press the iPhone power button.

The  3.0V and 1.8V voltage is supplied from iPhone power IC. If the circuit of 16.5V is abnormal, it will cause the iPhone can open the button that adds fingerprints, but there is no response when you add fingerprint. This voltage will be measured 16.5V when the fingerprint is opened and the iPhone Home button is touched by the finger.

If a fingerprint addition failure occurs, firstly use Fluke 15B+ Digital Multimeter to measure the iPhone to confirm whether there is 1.8V and 3.0V. If none of 3.0V or 1.8V, then measure whether there is a short-circuit phenomenon in this circuit. If short circuit phenomenon exists, then use rosin method to find the short circuit components. If it is open circuit or the resistance is normal but without voltage, check short connection FL4100 FL4105, re-install or replace the iPhone power IC.

If add a fingerprint without prompting for a failure, but there is no response when touching the home button with a hand, open the iPhone fingerprint function, click add fingerprint, when you touch the home button with your finger, measure the voltage whether is about 16.5V. If not, check short connection FL1407, use hot air gun and tweezers to replace U4040.

If the 3.0V and 1.8V voltage all is normal, but it prompts for failure when you add a fingerprint, check the diode data of interface 7/9/15/17/19. If it's open circuit, check the short connection and capacitor FL4110 R4111 FL4112 R4115 R4116, you can short connect it. If it is the iPhone home button fails, check short connection R4117.

More cell phone repair skills please visit VIPFIX Service Center www.vipfixphone.com

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