iPhone 7 Plus white apple restart repair

Machine model: iPhone7 Puls

Malfunction:Stuck on Apple logo can’t get into the system all the time.

iPhone 7 Plus white apple restart repair Figure 1.

Fault analysis: if it is 11, the system is mostly Baseband, usually Baseband, system program,Nand, battery Baseband, etc.
Maintenance process: Remove the motherboard. With the previous maintenance experience, it is probably Baseband problem. Directly disassemble the CPU shielding cover, measure Baseband S1~S5 Baseband, and find that the ground values of Baseband S1 ~ S5 Baseband are normal.

Connect the power supply switch, start up and test S1~S5 VCC for VCC output (VCC measurement is normal). Inadvertently, I found that during the measurement of VCC S1~S5 VCC, the motherboard current had exceeded current of change to 1A, and there was no restart.

iPhone 7 Plus white apple restart repair Figure 2.

There are two possibilities like this (1, related to Accessories of mobile phone. 2. The mobile phone PCB layer has Inveracious Soldering or is disconnected). Install the motherboard back, and install all Accessories. After this boot, it is found that Stuck on Apple logo restarts.

iPhone 7 Plus white apple restart repair Figure 3.

Now basically, it can be confirmed that the Accessories is a problem. Change the battery to DC power supply and turn it on again to test that the fault remains the same (the battery can be eliminated). Remove charging connector FPC(the mobile phone doesn’t have Stuck on Apple logo interface, and waited for or so to enter the system for half a minute). Put charging connector back in and test again (the mobile phone has Stuck on Apple logo card again).Replace charging connector directly, and then install and test, the fault has been perfectly repaired.