iPhone 6 SIM does not read troubleshooting

Machine model: iPhone 6

Malfunction: The SIM of the mobile phone can’t read it.

iPhone 6 SIM does not read troubleshooting figure 1.
Maintenance process:no SIM can be displayed to indicate that Baseband has been working, 1.8V VCC of SIM card is normal after disassembling,lighting cable of SIM card is only 26% lower than diode value of ground, and 26,normal value is at 260 or so.

iPhone 6 SIM does not read troubleshooting figure 2.

According to the map,lighting cable is connected with Current protection tube VR3101_RF and Baseband CPU U_BB_RF. Visual inspection shows that VR3101_RF has been removed by others.

iPhone 6 SIM does not read troubleshooting figure 3.

Remove Baseband CPU to measure PAD to ground diode value OverLoad, indicating that the PCB board is normal.

iPhone 6 SIM does not read troubleshooting figure 4.

Measure lighting cable solder joint of SIM card on Baseband CPU to ground diode value 26, which indicates that Baseband CPU is damaged, and it cannot be completely repaired because Baseband CPU cannot replace the machine alone.