How to fix iPhone 6S Plus volume buttons unresponsive failure
Sometimes, when we use a cell phone, there is a situation where the volume key reacts slowly. A customer sent us an iPhone 6S Plus. The fault described was that the iPhone was disconnected. When the iPhone was turned on, the screen was blurred. After the iPhone was replaced, the touch boost IC was displayed. The iPhone display returned to normal. However, the iPhone volume buttons do not respond when they test the iPhone. In this situation, how should we solve it, according to the following steps to easily repair the volume key which does not respond to the problem.
Now we need to test the iPhone again. Press the iPhone volume button , we found that the volume increase button does not respond, the volume down button and mute button are normal, compare the diode data to see if it is normal. Picture is as follows.
The 4th pin of the J4701 socket is the volume up button. The diode data is measured with a Fluke 15B + digital multimeter . The data is normal. Check the voltage, only 0.3V, and the normal voltage should be 1.8V. Consider whether the voltage drops due to a load leak on the path.
Check the iPhone schematic on WUXINJI Dongle. We know that the load of the circuit is capacitive C4713 and diode DZ4713. If the two components leak, the circuit voltage is pulled down. With these two components removed, the measured voltage is still 0.3v.
According to the iPhone schematics, we know that the circuit has no resistance, which means that the voltage is done through the internal CPU. Once again, the diode data is measured, and the data is normal, which means that the iPhone CPU has no virtual welding, which is caused by local damage.
Used to borrow from other circuit voltage, the method of modifying the volume button on the 1.8 V voltage. Looking for the latest circuit based on bitmap can be used to borrow the voltage, the modified circuit diagram is as the following picture.
Provide 1.8v voltage with the help of compass power supply, and connect 1K resistance of capacitor C3000 1.8v to capacitor C4713 non-grounding terminal. Then measure the fourth pin on J4701, which has a voltage of 1.79V.
Install the iPhone and test it., the volume button can work normally now.
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