Last week, a customer sent a iPhone 6 to
me, because the iPhone 6 flashlight not working, he has been send this iPhone6
to other place for repair, after checking, After checking, there was a line
that got into CPU short connected and CPU
was broken. And the maintenance personnel can't fix it. So the customers sent
it to our technical, and hope we can fix it. Let's see what's going on this
phone
First, turn it on and get into IOS to open
torch, finding that the flashlight cannot be turn on. After removing motheboard, we find that there is no flashlight
chip. Observing under microscope, we can
see that some pins are missing on solder pad of flashlight chip. The location
of solder pad is shown in picture 1-1. Then we call the customer and know that
the previous maintenance personnel do not assemble the flashlight chip after
tearing it down
1-1
Second, after counting under microscope, we
know there are 8 pins missing. Previous maintenance personnel might worry about
that high temperature would damage the CPU, so he violently pry up the chip. Through
schematic diagram, we know that the
missing pins are earth wire, LED1 power supply and the pin used to auto-lift
the voltage of flashlight chip, as shown in picture 1-2.The flashlight chip is
burnt because the pin used to auto-lift the voltage of flashlight chip is
dropped.
1-2
Third, solder these pins under microscope
and use BGA solder paste to solidify them. Assemble flashlight chip, as
shown in picture 1-3.
1-3
Finally, turn on iPhone and get into IOS to
open flashlight. The LED can be opened normally. The iPhone can back to normal
work.
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