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Still Can't Solve the iPhone 6S High Current Short Circuit Problem?

vipfixphone
Dec 7, 2017
1 min read

Received an iPhone 6 from one of our customer, the iPhone cannot be turned on properly now, he mentioned it was repair by other phone repair technician before, the first thing we are gonna to do is to disassemble and test with DC power supply, the iPhone logic board is measured with high current and CC light shows up. As shown in picture 10-10-1.

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. As shown in picture 10-10-2.

Power on and increase the current, we find the iPhone charging 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. As shown in picture 10-10-3

After checking on iPhone bitmap, 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. As shown in picture 10-10-4.