HELP! Why does my iPhone 6 can't connect Wi-Fi

If you come across this situation that your iPhone hasn't been connecting to Wi-Fi networks that it used to connect to automatically. You opened Settings > Wi-Fi to see what's happening, and discovered that that the Wi-Fi button is grayed out and you can't turn it back on. In this article, I'll explain why your iPhone's Wi-Fi is grayed out and the steps you can take to fix the Wi-Fi on your iPhone.

Received an iPhone 6 without WIFI, the customer said: "two mobile phone repair shop tried to fix it but didn't succeed". There are lots of solder flux cover on WiFi, it seems that WiFi has been replaced several times, a nearby resistor is also lost , the bottom of WIFI is scraped to copper wire, we can certainly confirm it's not the iPhone 6 WIFI module problem.

First remove the WIFI and boot device to measure the voltage of WIFI 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 1-1 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 1-2 and 1-3.

This reset signal has a capacitor and a pull-up resistor. The capacitance is next to WIFI. 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 WIFI, but the icon is still gray. Then we think the WIFI may be broken. Immediately replace a new WIFI chip, Bluetooth is shown up, WIFI also appeared, the fault is fixed now! Picture 1-4.