Guide: iPhone 7 baseband s5 working principle/ damaged process/repair method

Many people are confused about the iPhone 7 baseband failure because they don't know how to fix it. Luckily, here is guide for  iPhone 7 baseband s5 working principle, damaged process and repair method. 

For the iPhone 6 Plus touch M1, iPhone 6 baseband u1v1 and iPhone 7 audio problems, the traditional solution is that  welding iPhone touch IC or re-install touch IC to fix iPhone 6P touch problem, but after a while it need to be repaired again. 

After  continuing to explore and experiment, we all know that we can fix this problem completely by soldering the jump wire. The baseband u1v1 and audio problems can also be used in the same way. 

In fact, the real problem is that the first layer of these iPhone motherboard layer circuit lines is very fragile, 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.

After compare with the iPhone 7 and iPhone 7 Plus circuit line, we know that:

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

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

- The iPhone 7 motherboard layer circuit line, four grounding points are not connected

Based on the above conclusions, we know that the difference for iPhone 7 and iPhone 7 Plus are that 7P is 4 gnd together, and 7 is 93-98pin connected together.

Use BGA gravel tools to scrape off the circuit place that leaking copper, it is the first layer grounding circuit line. According to the above analysis, for the s5 circuit problem, the motherboard board line is almost broken, in a critical condition, resulting in gnd-s5 and even the entire baseband power supply poor working conditions, such as iPhone no service, no baseband, white Apple reboot, and finally complete short-circuit.

It's easy to fix it, we just need to use QUICK TR1300A 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.