iPhone 6s boot prompt no SIM card repair

Machine model: iPhone 6s
Fault phenomenon: prompt no SIM
Maintenance process: insert the mobile phone card to prompt no SIM, and you can’t see iccid in this machine.

iPhone 6s boot prompt no SIM card repair Figure 1.

The SIM card slot diode value is normal when the machine is disassembled. During the test, both the card VCC and the inserted card have 1.8V VCC. It seems that other conditions cause the SIM card not to be recognizedIt was found that 75_RFFE2_SDATA_BB this bus shorted to ground.

iPhone 6s boot prompt no SIM card repair Figure 2.

I looked at Boardview and went to many chips.

iPhone 6s boot prompt no SIM card repair Figure 3.

The 75_RFFE2_SDATA_BB bus diode value returned to normal when the UHBPA_RF high frequency power amplifier was removed.

iPhone 6s boot prompt no SIM card repair Figure 4.

iPhone 6s boot prompt no SIM card repair Figure 5.

Replace the removed one, replace it with a UHBPA_RF chip, install it and test it. The mobile phone card is recognized, the signals are normal, and the maintenance is finished.