Apple iPhone 12 doesn’t turn on

Apple iPhone 12 doesn’t turn on

Apple iPhone 12, the fault is not turned on,mobile phone If you fall, you won’t turn it on, and there is no response when you plug in the data cable; Because it is a fallen machine, we have to consider whether there are other problems caused by virtual welding in the middle layer, so we directly layer it. See below for specific steps:

“Machine model” Apple iPhone 12

[Fault phenomenon] No boot.

[Maintenance process] I received an Apple 12 machine, and the customer described that the phone stopped turning on when it fell, and the data cable did not respond.

Since it is a fallen machine, we directly disassemble it, take off the motherboard, and first look at whether there is a short circuit between the battery and the main power supply. After careful inspection, we find that the mobile phone is not seriously dropped and the shielding cover is not dented. Then we directly power on, and press the power button to find that the current has not changed. The resistance of the multimeter is normal, and the voltage of the power button is not 1.8v, and there is no voltage at all. Is it a power problem? However, because it is a fallen machine, we first consider the crystal oscillator. The crystal oscillator of 12 is ingeniously designed, just at the corner of the back of the upper motherboard, which is 108,000 miles away from the power supply, that is, on the back of the camera seat. Because it is a fallen machine, we have to consider whether there are other problems caused by virtual welding in the middle layer, so we directly layer it.

Apple iPhone 12 does not boot Figure 1

After delamination, it was found that the drop point was not very serious, but one corner of the crystal oscillator was already tilted, so we directly added some welding oil to remove the crystal oscillator, and sure enough, one corner of the crystal oscillator was already dropped.

Apple iPhone 12 does not boot Figure 2

Although the empty spot has no influence, it is obvious that the crystal oscillator has been soldered in vain just now. We put tin on the bonding pad of the crystal oscillator, put the crystal oscillator back and fix it with green oil, and then power on it to measure that the voltage of the power-on key has reached 1.6v Press the power-on key to take off normally.

Apple iPhone 12 does not boot Figure 3

[Maintenance result] Install the motherboard into the mobile phone, and start the test. The mobile phone is normally booted into the system, and the functions such as charging, WiFi, voice, compass, vibration and telephone are normal. The maintenance is over here.