iphone 6 water damage won't turn on current display 480mA
IPhone 6 cannot be turned on after dropping into water. After plugging the adjustable DC power supply, the current display is 480mA.
How to fix?
step:
Use multimeter to measure PP_VCC_MAIN, finding that it is short circuit to ground. We can feel that power supply chip is hot when energizing it. Put a layer of white rosin at the circuits of PP_VCC_MAIN voltage. The short circuit place is where the rosin will first melt. After a while, we can see that the rosin on a capacitor near power supply chip melts first, as shown in picture 6-1. Remove the capacitor, the PP_VCC_MAIN is not short circuit.
Picture 6-1
After plugging the adjustable power supply, iPhone still cannot be turned on. The current stops at 0.156A (156mA), as shown in picture 6-2.
Picture 6-2
We continue to measure and find that the voltage of RESET_1V8_L is 1.1V. Its location in bitmap is shown in picture 6-3. The material object is shown in picture 6-4.
Picture 6-3
Picture 6-4
We continue to measure and find that the voltage of AP_BI_I2C0_SDA is 0V. This point is not short circuit. The test point of signal AP_BI_I2C0_SDA in bitmap is shown in picture 6-5. Its material object is shown in picture 6-6.
Picture 6-5
Picture 6-6
Measure the circuit between AP_BI_I2C0_SDA to PP1V8 and it is not open circuit. Its resistance is 2.2kΩ. The location of pull-up resistor in circuit diagram is shown in picture 6-7.
Picture 6-7
After checking the circuit topography, we know that AP_BI_I2C0_SDA bus runs to U0201, U1202, U1700, U1501 light control IC and U1502. Based on experience, in watered iPhones, the chips without painted glue are very likely to be broken. Among these chips, only U1501 and U1202 is not painted glue. The location of U1501 in bitmap is shown in picture 6-8.
Picture 6-8
The location of U1202 in bitmap is shown in picture 6-9.
Picture 6-9
The material object of U1202 is shown in picture 6-10.
Picture 6-10
The material object of U1501 is shown in picture 6-11.
Picture 6-11
After removing U1501, the turn on current jumps normally. And the voltages of RESER_1V8_L and AP_BI_I2C0_SDA turn normal. Replace U1501 and iPhone can be turned on normally, but is displays nothing. There are many problems in water-damaged iPhones, they appear one after another. Now, we handle the no display problem. After measuring, the backlight voltage boost is 0V and D1501 has been damaged. The location of D1501 in bitmap is shown in picture 6-12.
Picture 6-12
The material object of D1501 is shown in picture 6-13.
Picture 6-13
Replace D1501 and measure the backlight voltage boost is 4V. After analyzing the circuit topography, the damage of U1502 will cause that voltage cannot be boosted. The circuit topography of backlight voltage boost of U1502 is shown in picture 6-14.
Picture 6-14
After replacing U1502, turn on iPhone and all functions are normal. The material object of U1501 is shown in picture 6-15.
Picture 6-15
How to fix?
step:
Use multimeter to measure PP_VCC_MAIN, finding that it is short circuit to ground. We can feel that power supply chip is hot when energizing it. Put a layer of white rosin at the circuits of PP_VCC_MAIN voltage. The short circuit place is where the rosin will first melt. After a while, we can see that the rosin on a capacitor near power supply chip melts first, as shown in picture 6-1. Remove the capacitor, the PP_VCC_MAIN is not short circuit.
Picture 6-1
After plugging the adjustable power supply, iPhone still cannot be turned on. The current stops at 0.156A (156mA), as shown in picture 6-2.
Picture 6-2
We continue to measure and find that the voltage of RESET_1V8_L is 1.1V. Its location in bitmap is shown in picture 6-3. The material object is shown in picture 6-4.
Picture 6-3
Picture 6-4
We continue to measure and find that the voltage of AP_BI_I2C0_SDA is 0V. This point is not short circuit. The test point of signal AP_BI_I2C0_SDA in bitmap is shown in picture 6-5. Its material object is shown in picture 6-6.
Picture 6-5
Picture 6-6
Measure the circuit between AP_BI_I2C0_SDA to PP1V8 and it is not open circuit. Its resistance is 2.2kΩ. The location of pull-up resistor in circuit diagram is shown in picture 6-7.
Picture 6-7
After checking the circuit topography, we know that AP_BI_I2C0_SDA bus runs to U0201, U1202, U1700, U1501 light control IC and U1502. Based on experience, in watered iPhones, the chips without painted glue are very likely to be broken. Among these chips, only U1501 and U1202 is not painted glue. The location of U1501 in bitmap is shown in picture 6-8.
Picture 6-8
The location of U1202 in bitmap is shown in picture 6-9.
Picture 6-9
The material object of U1202 is shown in picture 6-10.
Picture 6-10
The material object of U1501 is shown in picture 6-11.
Picture 6-11
After removing U1501, the turn on current jumps normally. And the voltages of RESER_1V8_L and AP_BI_I2C0_SDA turn normal. Replace U1501 and iPhone can be turned on normally, but is displays nothing. There are many problems in water-damaged iPhones, they appear one after another. Now, we handle the no display problem. After measuring, the backlight voltage boost is 0V and D1501 has been damaged. The location of D1501 in bitmap is shown in picture 6-12.
Picture 6-12
The material object of D1501 is shown in picture 6-13.
Picture 6-13
Replace D1501 and measure the backlight voltage boost is 4V. After analyzing the circuit topography, the damage of U1502 will cause that voltage cannot be boosted. The circuit topography of backlight voltage boost of U1502 is shown in picture 6-14.
Picture 6-14
Picture 6-15
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