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Solution: iPhone 6S Retains Signal After Removing SIM Card

Based on customer's description, iPhone 6S still preserves the signal after the SIM card is removed. According to our repair experience, this situation often can be divided into three kinds of situations:

1. abnormal card holder;
2. card detection pin problem;
3. baseband signal part problem.

Let's test the main fault before repairing.


Install the iPhone to test, we found there is still a signal even if the SIM card was pulled out. According to previous maintenance experience, first we use FLUKE digital multimeter to check the resistance of each pin of the card base, especially the resistance of the card detection pin (that is, the card switch).

After measuring, it is found that the card detection pin has no resistance value. At the other end of the R3401, the resistance can be measured, and the fault is determined in the card detection pin, which is broken.

Solution: you can use jumper wire to connect directly to the card detection pin without removing the card holder.


Connect R3401 to the eighth pin of J3001.

The operation is shown under Trinocular Stereo Microscope as the following pictures:

Install to test again, everything works perfect now.

Check more professional cell phone repair solutions from www.vipfixphone.com

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