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Phenomenon:  iPhone 7P reboot repeatedly while white apple logo appears.

Related question:  unstable current or voltage caused the fault.

We use the  DC power supply to check it, the value shows abnormal.

As attached the file describes maybe it is caused by the CPU, we try to flash it and check the specific error code.

But during we tested, it repeatedly reboot while cpu part is normal, the top of the iPhone hot is abnormal.

We know the top of iphone 7P is line and Wi-Fi, so the sources appears:

Quickly remove the iPhone motherboard and touch the iPhone WIFI IC, it's really hot, now we can confirm that there's something wrong with WiFi, and this serious hot is mostly caused by a short circuit in the capacitor. We can replace the WIFI IC, but the WIFI IC is close to the CPU in the iPhone 7 series, and after replace the WIFI IC, we still need remove iPhone NAND flash to unlock WIFI, it is not only troublesome, but risky, so we chose an easy and risk-free method--scrape WIFI with S1018 CPU Remover.

Because it was the first time we scraped the iPhone 7 WIFI, we don't know the specific location of those tiny components, so we put it under the Trinocular Stereo Microscope and scraped the entire WiFi module off. The marked position is short circuit, as shown in picture 11-4-1. Just pull it off, and use the Fluke 15B+ Digital Multimeter to measure it, now the data shows more than 300, it is normal.

Picture 11-4-2

Assemble the iPhone, there is no white Apple reboot phenomenon after booting, and WIFI also is normal. But, now the half iPhone LCD Display is dark and the other half is bright, as shown in picture 11-4-3. Fortunately, this problem is easy to solve.

Open the WUXINJI Schematic Diagram and check the iPhone, we found that this was caused by an damaged inductance FL3902, as shown in picture 11-4-4. Just get rid of it, and then use QUICK 861DW rework station to weld the jump wire on it.

After we finish the above operation, we test it again, the current and voltage shows normal. Then we reboot it, the fault phenomenon disappear as not repeatedly reboot.