According to customer's description, there were no any problems on his iPhone 6 Plus before, it can be normally used before, t. But after changing the iPhone Nand for memory capacity expansion by himself, it reports error 4014 when flashing it. As shown in picture 10-3-1. When we flash the iPhone device, it displays error 4014 before progress bar showing up. It is restored and the serial number could be recognized, which appeares after Nand expansion. This is usually caused by the iPhone USB chips leading to CPU problem. We get to know it UMT motherboard after disassembly, then remove USB chip U1700 to measure resistance from solder pad to CPU, we find that AP_TO_TRISTAR_ACC_UART6_TXD shows the infinite value, as shown in picture 10-3-2 and 10-3-3. And AP_BI_12C0_SDA is also broken, as shown in picture 10-3-4 and 10-3-5. The layer wire is disconnected, so we need to find out other connection point or digging for other holes, AP_TO_TR
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Before fixing iPhone 6s boot failure, you have to check if the iPhone device is broken or deformed. Open the iPhone screen to check the traces of water corrosion, the battery resistance is checked with normal value, then test the device with multimeter ( 2A am multimeter is recommended ) directly up voltage to 1.8A, it belongs to the high current system. Tear down all the accessories and starting with a single iPhone 6S motherboard , the result is the same, so you can be sure that the accessories or parts are ok. Before we fixed a lot of large current cell phone devices, power on and directly measure value, making sound is basically the components on VCC main power supply get problem, but the situation of current up to 1.8A is still relatively rare. After determining the measurement, we can confirm the problem is from VCC circuit, for big current device, you can use rosin with electric solder iron , apply rosin on the solder iron and work on VCC main circuit components, it wi
Got an iPhone 6s to repair, the customer mentioned the fault is no display, but it can receive calls, it got dropped accidentally last time, how to solve the problem? Let's see the details! After receive the iPhone, we press the iPhone power button , but no response. Disassemble the iPhone; take out the iPhone battery and supply power to it with DC power supply , the current is normal. Remove the iPhone screen , and then install the test screen, power on it and test it, the screen can display normally and appear white Apple interface. We thought the screen was damaged by dropping, but when we plug the original screen, it also can be light up, so we can exclude screen problem. The device light up, there are some problems when we are waiting to enter the IOS interface, blurry screen, grey screen, black screen, and it then cannot be wake up. Unplug the power and reboot iPhone, but the problems still exists. As shown in picture 9-11-1. Dete
Received an iPhone 6 from one of our customers, the problem is told that it can not boot, the iPhone device shows large short circuit when connecting with adjustable power supply . Disassemble the device we find that the flash position is hot, so we tear it down and find the solder pad is burned a hole. As shown in picture 9-6-1. PP_VCC_MAIN is short circuit, but it turns normal after removing L1605 inductance, however, the other end of L1605 to U1602 flash chip is still short circuit, so we directly dig from the burning hole till it's not short. There are 2 useful wire below the hole after we dig it: one is from U1602 flash chip E3 pin RCAM_TO_LEDDRV_STROBE_EN to rear camera 30 pin; the other is from CPU to transposon interrupt signal ALS_TO_AP_INT_L of J1111. Solder the 2 wire with jumper wires , and apply the green oil to solidify it. As shown in picture 9-6-2, 9-6-3 and 9-6-4. Then we repair the pads and fill the flash chip. As shown in picture 9-6-5 and
Have you ever met iPad touch screen problem before? We are going to fix a iPad Air 2 with the same fault, it can be reboot in a proper way, the only problem is that the screen cannot work at all, how to fix the frustrating problem? 1. First of all, measuring the iPad touch power supply, we can't find PPVDD_STINGER_BOOST voltage. PPVDD_STINGER_BOOST bitmap position of iPad as shown in picture 8-8-1. PPVDD_STINGER_BOOST principle diagram of iPad as shown in picture 8-8-2. 2. Diode value of L4001 inductor cannot be found when measuring with multimeter . As shown in figure 8-8-3. 3. In order to ensure the stability of the iPad, after replacing the L4001, by the way, D4001, C4014 and C4017 are replaced together. As shown in picture 8-8-4. 4. Connect and reboot the iPad Air 2 to measure the value again, we find PPVDD_STINGER_BOOST shows 20V voltage now. As shown in picture 8-8-5. 5. Finally, the touch function is tested as normal and the iPad motherboard is repaired successfully
Received an iPhone 6S Plus last week, according to customer's description, it's audio fault, the device was fixed before, but the same fault still exist. After accepting it, the first stop is to measure the audio parts, the original iPhone audio is not measured with large current, but in the contrary, a new audio IC shows large current, so we can determine that the original iPhone audio IC is good. Connect the iPhone device to check, it is not available for recording but the ringtone is normal. After disassembly, we find that large audio was not replaced before, first we are going to clean the iPhone motherboard . The electric current is normal when booting, the resistance measurement of U3500 M7 pin is on the ground. the point is the main power supply of PP_VCC_MAIN, if it is grounded, it will certainly clamp large current, so once again when we pinch, large current is not there. As shown in picture 8-6-1. Remove the shielding cap to measure the capacitors C3603 and