iPhone motherboard short-circuit and damaged iPhone chips are the two common reasons to cause iPhone 6 won’t boot. Here are some practical methods to fix these failure. With the help of iPhone repair tools and iPhone repair skills, you can fix it smoothly and quickly.
Measure the iPhone motherboard by DC power supply
If there is no power leakage when supplying power, but it will get leakage or large current once pressing the power button, this means the short circuit parts exist on one of the output voltage of power IC, measuring each output grounding resistance of power IC, find the short one, and check the related components.
If it shows power leakage or large current not booting, it must be one of the PP_BATT_VCC and PP_VCC_MAIN circuit has a short fault, first measuring the ground resistance of PP_BATT_VCC and PP_VCC_MAIN.
For iPhone short-circuit issues, the rosin method is the best way. After find the short-circuit part, remove it directly.
Check and test the iPhone chips, after confirm that iPhone IC is damaged, you can re-install it or just replace the new one, such as iPhone USB control IC, iPhone CPU, iPhone nand flash, iPhone compass IC.
You can flash the iPhone to check the flash process bar , and then confirm the iPhone damaged part.
Respectively measure each output of the bypass capacitance measurement resistance, find the short circuit parts. Use rosin to locate the specific parts!
In addition to the short circuit part would cause booting failure, the USB control IC damage will cause the failure of white apple screen. The damage of the compass IC will cause error 4013 after restoring white apple screen iPhone.
If iPhone gets blue screen rebooting or red screen rebooting, it is means the abnormal work of NAND parts, you can try to weld U0301, if still not work then restall or replace the iPhone 6 NAND chip(VC337).
If the boot is not responding, check whether the main power of U1401 output is normal. If abnormal, replace U1401, if there is main power output, replace the power U1201.
If the iPhone 6 set at around 100 Ma does not boot, connect with computer online, if it cannot recognize the hardware, it means the iPhone 6 CPU(VC542) does not work, try to reinstall or replace the U1202, if you can recognize the hardware, restore to see what error, if it’s 4005/4014/9/14/40, basically CPU or NAND problems, reinstall or replace the NAND. The compass IC damage will reports error 4013, replace the compass IC will solve the problem.
If the iPhone 6 doesn’t turn on because of water damage, clean and weld the small inductance and resistance around CPU and power IC, many small resistors or inductors can be corroded and damaged, they are hard to see by eys, you can use a VGA 7-45X Trinocular Stereo Microscope microscope(VC860) to check and solder.
If it’s a white apple keeps on the screen, the Ace assistant will see if it can read the information of the phone. If we can read the information, it will show that it can boot. The problem is in the display and touch part. The touch IC–U2402 U2401 can be reinstalled or replaced.