Professional Way for Repair iPad Air 2 Turn On failure

Most of repair way on Apple device are similar,  such as iPad Air 2 with iPhone 7.

First step we need to check is enter the DFU mode to check the sources faults, then decide what we should do next.

while connecting the iPad with computer to see if it is in the mode. If we can enter the mode, then it should be judged by reflash.

After connection, the computer was found in the recovery mode, but there is no serial number , it seems that the NAND flash chip is not recognized. In general, there were two kinds of faults: one is the NAND chip and the other is the circuit which connect the CPU and Nand is broken.

This is easier to deal with, remove the iPad Air2 NAND chip, nothing is abnormal when we use Fluke digital multimeter to measure the grounding resistance of the NAND pad, that we judge it may be the problem of the NAND chip. Remove the NAND chip off and put it on iPad NAND Test Fixture, it can't be read so we can judge that the NAND chip has problem. Replace the NAND chip and write a set of serial number code without ID on the test fixture, then weld the NAND chip back to the motherboard with QUICK 861DW Hot Air Station.

Reinstall the iPad to reflash, the NAND chip can finally be recognized now, also the progress bar works well!

The recovery process passes normally, and all the functions are tested well, repair ends here.

Summary: This reboot failure is caused by the damage of the iPad Air2 NAND flash chip.

 Then, we can clear see the results, sometimes booting failure always along with the NAND flash chip, so we may focus on this problem, which may be useful for the future's diagnostic.