iPhone 7 can’t start when it’s flooded, White apple restarted repair

iPhone 7 can’t start when it’s flooded, White apple restarted repair

Machine model: iPhone 7

Malfunction: the mobile phone water damage can’t be turned on, and Stuck on Apple logo restarts.
Maintenance process: look at the startup current after power-on. At first, the current is normal, but after the screen is lit, it will not go up and fall back to 0 at 500mA.
With experience, I feel that it is time for CPU to check whether Baseband is working normally or not, and Repeat welding Baseband is powered on normally. It is suspected that water damage corrode may have caused it. After turning on the phone Baseband, enter *#06# without IMEI, but the modem can see it.

iPhone7 can’t start when it’s flooded, White apple restarted repair Figure 1.

mobileAt the top left corner, there is no serviecs and there is no SIM card inserted. At this point, it can be determined that the RFFE bus is out of order. I’m a little confused. I’m not sure whether it’s Baseband or RF and other signal components. Because the Baseband problem of iPhone7 is particularly numerous.
Test whether Baseband cpu caused it with i4 reserved data Update System. If it can’t be activated, it can be sure that Baseband PCU caused it.

Update System passed smoothly, and the Baseband CPU circuit of this iPhone7 is normal. At first, it is already the 13.1.2 system. Next, it is to fix the RF signal part, and there will be a signal when the components related to RFFE are repaired.

The following picture is the bus diagram of Xinzhizao Soft about iPhone7, which is written in great detail. With this picture, the RFFE bus can be repaired to a great extent.

iPhone7 can’t start when it’s flooded, White apple restarted repair Figure 2.

From the figure, we can see that there are seven pairs of RFFE buses. If one bus goes wrong, it will cause problems with the RFFE bus, which will lead to no serviecs or prompt that the card is not inserted. Experience show that that small RF xcr0 _ RF on RFFE1 and the large RF xcr1 _ RF on RFFE4 are prone to problems.

iPhone7 can’t start when it’s flooded, White apple restarted repair Figure 3.

It doesn’t work with big RF, and then with small RF, boot test, full signal.

iPhone7 can’t start when it’s flooded, White apple restarted repair Figure 4.

The data Update System should not be reserved first.Update System is risky after all. According to the iPhone7 bus analysis of Xinzhizao Soft, it is more appropriate to change the size Update System first.