A iPhone 6S cannot boot because of short circuit. Let's check the error details and fix it!
Press the iPhone power button, the iPhone 6s has no response. Disassemble the iPhone, and measure it with DC power supply, it shows large current, and CC light shows up.
High
current is usually caused by damaged components on iPhone
battery voltage VBATT or on the VCC_MAIN circuit. The VBATT
resistance value is measured normal, and the voltage of the VCC_MAIN is
measured to 0.
Power
on and increase the current, we find the iPhonecharging chips and bell ring amplifier under the motherboard burn
hot, so dismantle it directly then measure the value, it also makes short
circuit to the ground, and still we can feel hot around. In order to find out
the trouble spot accurately, fumigate the rosin and find that the charging tube
is hot, which indicating that the short-circuit is not caused here.
After
checking on iPhone circuit diagram, we find that
the iPhone backlight chip is very vulnerable for the connected components in
the VCC_MAIN , directly remove the motherboard shield, we find this part was
repaired before since both inductor and chip are get some broken. Take off the
chip which is measured with normal value, then we replace with new chip and
inductor.
At last, assemble the iPhone, and turn it on again, now it's going to boot up. The iPhone has been fixed!
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