iPhone XR actviation failure- Solution!

 Here is an iPhone XR with actviation failure, the iPhone XR can't be activated, it stucks on SN interface. Hers is a solution to fix iPhone XR actviation failure.

Disassemble the iPhone XR. Use qianli 3D screwdriver and CPB screen separator to open the iPhone XR screen. Remove the iPhone XR display assembly, disconnect the battery, and then take off the iPhone XR motherboard.

We noticed that this iPhone XR has repair marks.  The baseband shield cover has been disassembled, and there is repair sticker on it. And we found that the iPhone Nand flash also been repaired before, because there are some black glue around it.

Remove the repair sticker, obviously the iPhone baseband has been repaired before, the capacitors and resistors around it has been corroded and blackened.

Use Jabe UD-1200 soldering iron to smoke rosin to the motherboard, so the solder oil for the bottom pin of the IC assembly can be replaced.

Use hot air gun and tweezers to remove the iPhone baseband. Put the iPhone motherboard under a microscope to observe, the iPhone baseband IC doesn't looks good. Apply some solder paste to the baseband, and then reballing it.

After reballing, assemble the iPhone XR to test it, but the failure is still the same.

Use ADMS9 digital multimeter to measure the resistance value for the iPhone baseband power supply, we found all resistance value measured are normal.

Check iPhone motherboard again, we found the RF IC also has been repaired before, use hot air gun and tweezers to replace the RF IC, and then assemble the iPhone XR.

Now restore the iPhone XR with iTunes, and then follow the tips to activate the iPhone XR, it goes well, the iPhone XR was activated successfully.

Troubleshooting: iPhone 7P get boot failure after dropping

This iPhone 7P get boot failure after dropping, press the iPhone power button, the iPhone has no response, in a word, the iPhone 7 plus won't turn on.  We need to fix it.

Use phone disassembling tools to disassemble the iPhoen 7P, remove the iPhone display screen, disconnect the battery, and then take out the iPhone 7P motherboard.

Use UNI-T UTP3305 DC power supply to measure the iPhone 7P motherboard , trigger it, the current up to 60mA and then downs to 0, the current jumps like this over and over again, which is abnormal.

Use digital multimeter to measure the relevant voltage for the RAM, they all normal.

As we know, for the drop-damaged iPhone, the iPhone CPU virtual welding is more likely. Put the iPhone motherboard on the PCB holder fixture, and then put it under a Trinocular Microscope.

Use BGA graver blade to remove the black glue around the iPhone CPU to check if the iPhone CPU is virtual welding, but it's normal.

Based on our experience, the RAM for drop-damaged iPhone 7P is easy to short, let's remove the iPhone CPU, after removing CPU, we found the solder pad missing some pins.

Use JBC CD-2SHE soldering iron to clean the solder pad, and then solder the missing pins. After handling the solder pad well, install the iPhone CPU back to the motherboard.

Now measure the iPhone 7P motherboard with UNI-T UTP3305 DC power supply, the current tested is normal.

Install the iPhone 7 Plus, press the power button, the iPhone 7 plus is turned on successfully.