IPhone 7 restarts (1.8V power supply is pulled down)

IPhone 7 restarts (1.8V power supply is pulled down)

IPhone 7, the fault is that the white apple can’t restart into the system. When the single board of the machine was powered on, the current triggered the take-off to be normal, and it was restarted at 300mA. I immediately thought of the common fault of the seventh generation, and the bad audio led to the restart of the white apple. However, the specific reasons have to be analyzed in detail, so as to solve the problem, then learn more about it!

[Fault model] iPhone 7

[Fault Phenomenon] Restart

[Maintenance process] I received a machine sent by a customer for repair, the model is iPhone 7, and the fault is that the white apple can’t restart into the system.

IPhone 7 restarts Figure 1

When the single board of the machine was powered on, the current triggered the take-off to be normal, and it was restarted at 300mA. I immediately thought of the common fault of the seventh generation, and the bad audio led to the restart of the white apple.

However, you can have a look at the brush first. The brush can be brushed normally, but when you take the progress bar, the white apple restarts. Measure the power supply resistance of the motherboard and find that the resistance of the power supply of 1.8v is only 33, which is obviously not lowered by anything. Look at the components on the line and find that a power supply tube next to the CPU is burnt black.

IPhone 7 restarts Figure 2

IPhone 7 restart figure 3

Directly deduct and measure the resistance of 1.8V It has returned to normal. Look.blueprintDirectly short-circuit the A1 and A2 pins of this power supply tube, and then start the test, and refresh the machine again to start the machine.

IPhone 7 restarts Figure 4

[Maintenance Result] Install the motherboard into the shell.mobile phoneIt can be turned on normally, and the functions of WiFi, Bluetooth, voice, charging, fingerprint, taking photos and making phone calls are all normal, so the maintenance is over.