The customers send an email to us about hers iPhone without Wi-Fi connect , it is the third time she sent to the repair shop . We disassemble it and found lots of solder flux covered on Wi-Fi and the nearby resistor was lost, the bottom of Wi-Fi was scrapped to copper wire. We doubt there exist others failure which caused the Wi-Fi Module problem. Let we start to the check.
First remove the Wi-Fi and boot device to measure the voltage of Wi-Fi bottom board pin, we find that 14 pin has no signal voltage, it should be 1.8V. The problem comes from here. Using a digital multimeter to measure but no resistance, so we use WUXINJI bitmap to check and find it is directly through CPU, is it the bottom board wire disconnection?
It can be seen from the bitmap 10-25-1 that the iPhone 6 bottom board wire is really disconnected.
Now we have to see if there is another way, continue to look at the principle diagram Apple 6. As shown in picture 10-25-2 and 10-25-3.
This reset signal has a capacitor and a pull-up resistor. The capacitance is next to Wi-Fi . There is no resistance in the measurement. This is hopeless, then we look at the pull-up resistor again, find it is on the back of the iPhone 6 CPU from the bitmap, and it's very close. Measuring resistance is 446, then directly solder jumper wire, install Wi-Fi , but the icon is still gray. Then we think the Wi-Fi may be broken. Immediately replace a new Wi-Fi chip, Bluetooth is shown up, Wi-Fi also appeared, the fault is fixed now! As shown in Picture 10-25-4:
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