Today, we are going to talk about the iPhone 6 Plus shows black screen after booting. Its current jumps normally, and it can be brush smoothly. However, when you press the power button, the iPhone screen shows nothing, it just no display.
Disassemble the iPhone, take out of motherboard, measure the diode data of display connector and display condition, all is normal. Then we install the iPhone CPU and test it, the fault is still existing. Check the iPhone circuit diagram to measure the MIPI module conditions (required power supply, pull-up resistor, pull-down resistor, etc.). As shown in picture 1 .
When
measuring PP1V0, there is no voltage, the resistance value to ground is 0, we
doubt CPU is not installed properly, but it's the same fault after
reinstalling. Remove CPU to measure motherboard without short circuit, CPU ground value is also not short circuit. Reinstall
again, it's still short circuit. Removed and meausre the iPhone CPU on the ground
value, three points are found short circuit on it, we finally find it's CPU
problem.
Study
on the circuit diagram to know this is just a MIPIC short circuit, it's just
one module short circuit, can we pass it? (the 5 test points is the same way in
the circuit diagram, which should be interconnected, but for this iPhone fault,
the above 3 points is VDD10_MIPIC, the following 2 points are VDD10_MIPID,
which belong to two different modules, VDD10_MIPIC short circuit module did not
affect the VDD10_MIPID)
Cover
these three pins with green UV oil, as shown in picture 9-12-4 .
Finally, installed
and value the value, we find it is not short circuit now, after the trigger, it
smoothly light the iPhone screen,
functions are tested all OK. The iPhone 6 Plus has been repaired!
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