Solution: iPhone 7 Baseband Fault

Phone 6 Plus touch M1, iPhone 6 baseband u1v1 and iPhone 7 audio problems are very common for phone repairmen. At first, we can weld iPhone touch IC or re-install touch IC to fix iPhone 6P touch problem, but after a while it need to be repaired again. Later, we figure out that we can repair the problem by jump wire. The baseband u1v1 and audio problems can also be used in the same way. The first layer of these iPhone motherboard layer circuit lines is very fragile and easy to disconnect or virtual welding, some are not broken by the naked eye, but in fact it is almost disconnected, weak links, at a critical point.

Now, let's back to iPhone 7 baseband problem, most people think it is Qualcomm baseband problem, and we think it's still the same as before, it's iPhone motherboard design flaws. 

Check the working schematic diagram of the iPhone baseband power supply through WUXINJI Dongle, it's amazing, as shown in picture 1.

Put iPhone 7 and iPhone 7 Plus under the Stereo Zoom Microscope to check, we can see the difference between them， as shown in following pictures.

There's ground wire underneath the 83-88pin layer

The iPhone 7P motherboard layer circuit line, four grounding points are connected

iPhone 7 main board circuit lines, four locations are not connected.

Therefore, from the above picture, we know that the difference between iPhone 7 and iPhone 7 is that 7P is 4 GND together, and 7 is 93-98PIN connected together.

Scraping the location of the leakage copper, it is the first grounding circuit. So, what should we do now?

According to the above analysis, for the S5 circuit problem, the main board line is almost broken and is in a critical state, leading to the poor working conditions of GND-S5 even the whole baseband power supply, such as iPhone without service, no baseband, white apple restart, and final completion. Short circuit.

It's not difficult to repair, we just need to use QUICK 861DW hot air rework station to solder a jump wire between 88pin and 93pin,or you can scrape off grounding circuit line and then solder a jump wire. This method is suitable for initial failure, baseband circuits are not low on the iPhone. 

Some iPhone has been repaired for several times, the iPhone baseband is damaged; the resistance of s5 measured by digital multimeter is lower than normal data. Use above method also can fix it, but it may be has no service or unstable use life issues.

For iPhone 7 series 4013 error, there is small probability to fix iPhone 7 series baseband s5 4013 error by modifying the circuit, borrow the voltage, or the increasing the resistance. 

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