A Guide To Repair iPhone 6S SIM Card Identification Failure

Some users have reported that the iPhone 6 cannot recognize the SIM card. Why does the iPhone 6 not recognize the SIM card? How to solve it? In response to this issue, in this article, our phonefix shop team will teach you how to fix it.

We received an iPhone that it could not recognize the SIM card. The first step was to disassemble and check it carefully. The iPhone has been fixed before. It is a UMT board. The repaired area is the baseband power supply, which has a lot of solder paste.



Use digital multimeter to measure the voltage of each pin of the socket at the moment of power-on, all the SIM-RST SIM-CLK SIM-DATA have instantaneous voltage, only SIM-VCC does not.

According to past repair experience, there are 2 problems in the power supply of SIM card:

1. baseband power supply.
2. capacitance resistance.

The baseband power supply has been repaired, without considering power supply. It should be a small capacitor or a small resistor problem. As shown in picture.

By checking the WUXINJI circuit diagram, it is found that the small capacitance and the resistance are under the shield cover, carefully cut off a part of the shield, and observe the small capacitance under the Trinocular Stereo Microscope. It is found that the color of a small capacitor is a bit different, so we remove the damaged one. As shown in picture.


                                   




Now, the power supply pin of the SIM card is measured again, the voltage is normal.

Reinstall the iPhone 6 and insert SIM cart to test, the card can be recognized, and other functions are also tested OK.

Summary: a lot of repairmen choose to replace parts, no more thorough understanding of the principle of the mobile phone, and they do not know how to find out after replacing a few IC, in fact, a lot of faults are in small capacitors and resistors or inductors.

For any technical support, please visit www.vipfixphone.com.