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IPhone6/6Plus heavy fall does not turn on the fault repair

by:YoukingTech     2021-08-29
Posted on 11.18 iPhone6/6Plus fell heavily and does not turn on for troubleshooting. You can go to the Apple after-sales repair point at B1, 21st Floor, Zhiyuan Building, No.389 Qingnian Road, Wuhua District, Kunming. Method/Steps Symptom: The phone will not be turned on after a heavy fall. Repair process: After getting the phone, carefully observe it before repairing it by hand. The motherboard is intact and there is no obvious trace of breakage. Turn on the power and watch the current change. The result of the change in current is a short circuit and a large current. There is a classic method of repairing a machine called the rosin method. The principle is to determine the point of failure based on how fast the rosin melts, and the principle is based on the short circuit of the motherboard. Because the power meter is short-circuited directly, adjust the power meter voltage to 2.8V, and then smoke the rosin to see the degree of melting. Obviously the electronic switch tube Q1403 melts first, remove Q1403, and then measure the resistance of the foot. As a result, B1 (B2, B3, A2, A3) of Q1403 is grounded, and the normal resistance value is 325. Then, where do we look at this connection? There are so many places in this road. Many people don't know how to continue. We can only check one by one. Starting from the simple risk, Q1403 has been removed, and it is directly short-circuited, as shown in the figure: C1C2C3 connects to A2A3B1B2B3 at any point. Next, remove the baseband power supply, power supply, and loud audio one by one. After dismantling, this road is still short circuited. The rest is backlit IC U1502, then smoked with rosin. The backlight IC and the nearby C1552, C1597, C1530, C1531, C1505 are all easy to break. We directly removed the backlight IC and found that it was still grounded. Then, the 5 capacitors were deducted, and then the power-on test was finally not grounded. The next step is to remove it. Make up all lost things. After installation, power on and test. The phone is resurrected again. 1
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