The front camera of iPhone 6 Plus is unavailable after dropping, but all other functions are normal, and you can switch freely between front camera and rear camera. The problem is when you use iPhone front camera to take pictures, it shows black screen. This problem is generally caused by data hub. In this case, it is likely to be caused by the disconnection or iPhone CPU false welding.
Step 1
Disassemble
and install a new camera, same fault phenomenon remains the same, the problem
is determined on the iPhone 6 Plus motherboard.
Step 2
Power
off the phone and measure the ground value of the camera interface, there is no
any problems has been found, also the voltage needed for the camera is measured
normally. This is a rare situation. If the CPU is false welding, the resistance
shouldn't be normal, so there is almost impossible for getting a bad CPU.
Step 3
Test
the interface resistance again, infinity is detected when the 19th pin
AP_BI_FCAM_SDA_FONN is measured. Many
tests found that sometimes it's infinite, sometimes more than 500 of the
resistance, but according to the data cable comparison found that under normal
circumstances, it should not exceed 500. Measured valure on multimeter is as shown in picture 1
Tracing
the source, it was found that the AP_NO_FCA_SDA_CONN was connected to the CPU
by inductance, and the resistance of the 1 pin measured by FL1114 was normal.
Step 4
After
measuring FL1114's 2 pin infinity, we find that some inductance is loose, after
sodering with phone rework station, 19 pin resistance become normal.
Finally, assemble the iPhone, power on and test it, the front camera can take pictures normally now!
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