What do I actually have to be compelled to be compelled to undertake and do if your iPhone seven won’t activate once being dropped? the matter might even be caused by a code package crash or a classy hardware issue. we've open Associate in Nursing iPhone half-dozen won’t activate guide video, and now, we've got a bent to tend to tend to tend to received Associate in Nursing born iPhone seven that cannot activate. the matter was finally detected as hardware being short-circuited. Here we've elaborate troubleshooting procedures.
Diagnosis
Take apart the phone and disconnect the battery, then connect the phone with the DC Power provide and press the power button to power on. this reading of the meter jumps to 350mA then stays still, that is abnormal and indicates that the logic board is short-circuited.
Disconnect the power provide and eliminate the logic board. Run diode measurements on capacitors around power IC one by one. All the values unit ancient except C1823 – It displays zero, that indicates that C1823 is short-circuited. From the schematics, we've got a bent to tend to tend to ar ready to see that C1823 is that the filter device of PP1V8-SDRAM, and it's directly connected to hardware SDRAM.
Repair
Attach the logic board to the PCB Holder, and take down the shielding cowl by heating with Hot Air Gun, then exclude hardware SDRAM with CNC Chip Grinding Machine. once chip grinding, attach the logic board to the PCB Holder and clean it with PCB Cleaner, then exclude the black adhesive around with Sculpture Knife. After that, apply some BGA Paste Flux to the bonding pad. Align the new SDRAM to the correct place(Don’t reverse the direction), then solder with Hot Air Gun. once cooling for five minutes, clean whole with PCB Cleaner.
Testing
Connect the phone with the DC Power provide, then short Pin thirteen of J4504 to rock bottom with the pincer to trigger the power on the system. This time, this reading on the meter is ancient.
Get the logic board assembled and buckle the show assembly. Connect the phone to the computer, then press and hold volume down and power button to urge into DFU mode. Restore the phone via iTunes. Once done, insert the SIM card and activate the phone. once testing, All the functions work normally.
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