Wiser mind for iPad 5 NAND Repair

While the customer said, the iPad happens error 40, at the same time, it can't be turned on. 

Usually we will check the circuit board, so it is necessary to disassemble it, check the iPad motherboard.

First step, we need to connect it with the DC Power Supply, trigger it to test the current, the current stuck in around 40mA. Connect iPad to the computer and DFU restore it, it reports error 40. After entering the restore mode, we found the SN can't be identified.

According to the error code, we judged that it's the problem of iPad Nand flash or the circuit of the iPad Nand flash. Disassemble the iPad 5, take out the iPad motherboard, we found the iPad Nand flash has the trace of disassembling. Measuring the 1.8 and 3.3V of the iPad Nand flash, both doesn't have the power supply.

Check iPad schematic diagram via WUXINJI Dongle, we can know that power supply for both sets of circuits is converted from U3850.

Because the iPad Nand flash was disassembled, so we suspected that the power supply tube was virtual welding. Re-install it, the power supply is back to normal, but the iPad still won't turn on.

Now we need to use Quick 861DW hot air reworks station to remove the iPad Nand flash, after remove the iPad Nand flash, we found some pins of the solder pad are missing.

Pic 1

Refill the solder pad, installing the iPad Nand flash to the iPad motherboard. Assemble the iPad and test it, now the iPad is turning on smoothly, the repairs end!