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How to Fix iPhone 7 WiFi Disconnection

Doris Qin
Nov 14, 2017
2 min read

Received an iPhone 7 today, the Bluetooth can work normally, but the WIFI icon is gray and cannot be opened. Press the iPhone power button, we are going to test the other functions first, all is fine, the only problem is WIFI cannot be turn on. As shown in picture 9-5-1

After we enter the IOS system, we still cannot see the MAC address of WIFI, as shown in picture 9-5-2

Not even Wi-Fi addresses like this are basically caused by the iPhone CPU does not recognize the Wi-Fi chip, the customer said the iPhone has been dropped, we suspect that the chip was damaged or empty solder. Test the Wi-Fi working conditions before removing the chip. As shown in picture 9-5-3.

Use multimeter to measure the diode data, no problem found, is it really the Wi-Fi chip that's broken? Now we only can remove it and replace the new one. To replace the iPhone 7 Wi-Fi chip, you need to remove iPhone NAND flash and unlock. Now, we remove the Wi-Fi chip, and then we found that the solder pad of Wi-Fi chip dropped four points, the position of circuit diagram as follows

These pins are on the PCIE bus, and it passes through coupling capacitor to the CPU. Ready to replace the chip, but replacing the chip requires removing the NAND flash, so we’re trying to make up the pins on the chip. Scrape out solder joints, weld the jump wire, and paint the green UV oil, and then plant Tin, welding it with rework station. Well-welded chip as shown in the picture 9-5-5.

The small pins on the edge of the chip can be used to test whether it is properly welded. After welding, measure the diode data with multimeter, it is normal. Boot it and test it, the failure has been repaired, as shown in picture 9-5-6.

Finally, we can see the WIFI address on the phone, which shows the CPU has already identified the chip. The WIFI can be turn on now, as shown in the picture 9-5-7. Test it for a period of time, all is fine, send the iPhone 7 back to the customer.