Apple iPhone 6s Plus has no 4G mobile network fault repair

Check “About this machine” and find that there is no baseband, make up the dropped inductance and install the motherboard into the machine. Boot test shows that the version of “Modem Firmware” in “About this machine” is normal, indicating that the baseband has been working normally.

Machine model: Apple iPhone 6s Plus

Fault phenomenon: The customer described that the mobile phone was still in good condition, and suddenly there was no network, no phone call and no 4G mobile network when it was used.

Maintenance process:

After receiving the mobile phone, there was no service for the card insertion test. After checking the “About this machine”, it was found that there was no baseband and no 4G mobile network. By asking the customer, it was known that the mobile phone had not entered the water, but the child had used it and the mobile phone had fallen.

To deal with this situation, the baseband power supply should be welded before disassembling the machine. If the welding fails, a baseband power supply will be replaced, and the fault remains. Wondering if the baseband was soldered, I removed the baseband shield and found that there was an inductance soldered on the side of the baseband. When I touched it with tweezers, the inductance fell off.

Apple iPhone 6s Plus does not have 4G mobile network fault maintenance. Figure 1

Open Xinzhizhao software, and look at the dot bitmap. It is found that this inductor is a step-down inductor powered by S2 output from baseband power supply. The virtual welding of the inductor leads to the lack of S2 power supply for baseband power supply, and the baseband power supply can’t provide power for the baseband after the second step-down, so the baseband doesn’t work, and finally the mobile phone has no 4G mobile network signal.

Apple iPhone 6s Plus does not have 4G mobile network fault maintenance. Figure 3

Make up the fallen inductance and install the motherboard into the machine. Boot test shows that the version of “Modem Firmware” in “About this machine” is normal, indicating that the baseband has been working normally. In addition, the upper left corner of the mobile phone shows that China Mobile’s 4G signal is full, and the fault is perfectly repaired.