Repair iphone 6 Plus HDD PCB large Area Drop point
Customer said that 3/4 solder joints have been dropped when he had the storage expanded. After jumping wires and rooting, iTunes reported error 4005 and screen displayed white Apple logo.
Repair Process
When I receive the motherboard, it has no EEPROM and many jumping wires on PCB with green oil.
After observing the outer looks of the motherboard, I use multimeter to measure the diode data of all the solder joints and they all have data. But, comparing these data with that I get from my previous repair cases,I find that pin G5 should be about 700 and J5 should be about 500 (notice: different multimeter shows different data). While these two joints is about 700. The two data should not be the same. I guess that someone must jump the wrong wire.
when scratch the green oil carefully, I find that there is a wire and a via. Measure its diode data. The data of wire is about 700 while the data of via is about 500. Now I can be sure that the customer has jumped the wrong wire.
Rejump the wire and paint green oil. Measure the diode data of pin J5. It is about 500. In case of other problems, measure the diode data of all the solder joints again and find other two joints that are jumped the wrong wire. Fix them one by one. Although that costs me a quarter, it is useful.
After assembling the EEPROM, root it again. The screen still displays white Apple loge without the progress bar. But iPhone now can recognize EEPROM because it shows white Apple loge in seconds. I presume that CPU is pseudo soldering or the board is disconnected. Considering the stability of whole iPhone, after discussing with customer, I use the other workable motherboard to replace the original one. Trouble is removed.
Repair Process
When I receive the motherboard, it has no EEPROM and many jumping wires on PCB with green oil.
After observing the outer looks of the motherboard, I use multimeter to measure the diode data of all the solder joints and they all have data. But, comparing these data with that I get from my previous repair cases,I find that pin G5 should be about 700 and J5 should be about 500 (notice: different multimeter shows different data). While these two joints is about 700. The two data should not be the same. I guess that someone must jump the wrong wire.
when scratch the green oil carefully, I find that there is a wire and a via. Measure its diode data. The data of wire is about 700 while the data of via is about 500. Now I can be sure that the customer has jumped the wrong wire.
Rejump the wire and paint green oil. Measure the diode data of pin J5. It is about 500. In case of other problems, measure the diode data of all the solder joints again and find other two joints that are jumped the wrong wire. Fix them one by one. Although that costs me a quarter, it is useful.
After assembling the EEPROM, root it again. The screen still displays white Apple loge without the progress bar. But iPhone now can recognize EEPROM because it shows white Apple loge in seconds. I presume that CPU is pseudo soldering or the board is disconnected. Considering the stability of whole iPhone, after discussing with customer, I use the other workable motherboard to replace the original one. Trouble is removed.
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