How to fix iPhone 5S boot failure

While iPhone has updated to 10,  more and more people prefers to choosing iPhone 6 or 7. But there still exist some people would rather choose iPhone 5S, cuz its beautiful size,  if it happens some faults, we still need to repair it.

1. Large current and won't boot

This situation is caused by short circuit in PP_BATT_VCC, PP_VCC_MAIN, the solution can reference to power leakage repair.

2. No leakage without turning on, large current when press the power button

This is the case that the output of the power IC circuit is short circuited, you can measure the resistance of the output to the ground with Fluke digital multimeter one by one to find the short circuit parts, then find the specific short circuit parts with the method of detecting the leakage.

3. Turn on with 50 Ma Current

This situation is mostly iPhone CPU or NAND pseudo welding or damage, which is very difficult to repair! Because the NAND chip can not be replaced alone, the cost of replacing CPU is also very expensive. And you can't make sure it will be 100% successful, so it is better to give up in this case.

4. White Apple stuck on screen, blue screen, line crash in English, red screen or color changed after restart.

For white apple stuck on screen problem, first make clear whether it is not to turn on or just display is not normal, you can turn on the iPhone to connect Ace assistant, if it can turn on normally, then it can be online and Ace assistant can read the information of the mobile phone, then it means the problem is from the display part, the solution is to reinstall or replace touch IC.

5.U2 damage will cause reboot failure, white apple stuck on screen, iPhone start at 200MA.

6. If iPhone is in the recovery mode, first flash to see what the error, if it is error 4013, you can replace a iPhone compass IC or U2, if it still doesn't work, generally it is the NAND damage, replace the NAND flash chip, if it is error 9 or 14, the U6 or NAND get damaged, first replace U6, if not working, then you can replace Nand chip.

7. if the restart current is about 50 Ma, computer will automatically enter the DFU mode, which is mostly caused by CPU abnormal work, check whether some of the resistance of the peripheral CPU are pseudo welding or falling off.

If you want to DIY it, maybe the above-mentioned fixing way will be useful for you.