When your iPhone has got wet and water-damaged and turn on current jumps at 0mA and 120mA repeatedly, you dropped it, in the bath? or the toilet? and now you want to dry it out, fix the water damage, and recover the data inside, you have come to the right place. It's a sad fact that particularly iPhones get dropped and damaged all the time, Probably the most common is almost certainly water damage and you should be aware of the cause by software errors or physical damage and fast fix it. water-damaged iPhone 6S current jumps trouble Check Dismantling your iPhone Step 1 First things first, Connect the adjustable DC power supplyto check current and it shows electricity leakage is 60mA and 120mA if press the power button, it drops back to 0mA and repeats the jump. take photos for watered places and clean the motherboard Step 2 secondly，as for the water-damaged iPhones, we first take photos for the watered places and then clean the motherboard, That will be beneficial, because we find some problems during the repair process, we can refer to those photos to exclude badly eroded components.Remove CPU and the shield cover on baseband, finding four eroded places, They are backlight power supply chip U4020, display power supply chip U4000, charging management chip U2300 and small audio chip U3700. energize the motherboard finding abnormality Step 3 After cleaned, we can energize the motherboard and find that the electricity leakage current turns less, only about 20mA, the current jumps from 70mA to 0mA repeatedly. Measure the power supply voltage of CPU U0600, finding no abnormality, Measure the voltage of I2C bus, finding that the signal I2C0_AP_SCL only has 1.1V, The I2C0 bus in circuit diagram is shown in picture:
The I2C0 bus in bitmap is shown in picture :
The material object of I2C0 bus is shown in picture :
remove the display chip Step 4 Check deenergize motherboard and measure the diode data of I2C bus, if there are 404 and 430 which is normal, Viewing the eroded components photos, we can that the display power supply is damaged, because the backlight chip is painted with glue, which is not easy to be damaged, remove the display chip U4000. What to do next Step 5 Then after removing the display chip U4000,try energize it, if the current is still the same, While I2C0 bus voltage turns normal. this problem may be caused by power supply chip U2000 and backlight chip U4020, maybe that the backlight chip U4020 causes the turn on failure is related to two groups of signal, One is I2C0 bus, the other is backlight brightness adjustment signal‒backlight chip DWI bus which runs to power supply and CPU. The DWI bus interface in schematic diagram is shown in picture :
SCK can be measured at the resistor R4020 Step 6 We know the backlight chip DWI bus has SDI and SCK two signals, by measuring the diode data to ground, whether backlight chip U4020 is workable or not. SCK can be measured at the resistor R4020 in picture :
SDI can be measured at the test point PP1002 in picture :
After dealing with this problems iphone back to work again Step 7 Next, measuring the diode data to ground of R4020, we find that it is short circuit, we can remove the backlight chip U4020 and energize motherboard to turn it on, the current will be jumps to 1A, After assembling backlight chip U4020 and display chip U4000, the white Apple logo appears and iPhone gets into IOS normally. When dealing with the problems about the turn on failure after being watered, we can ignore the removed chips if they do not effect the turn on process,the current jumps normally, we reassemble them, your phone back to work again. In this article we explain the best strategies for dealing with a water-damaged electronic device, If the above measure have no effect, then you need professional to check your iPhone, You can find many phone repair guide from vipprogrammer.