iPhone 6 current shows 480mA and cannot turn on, how to fix it?

No matter when time, you should keep you iPhone far away from water, because it will damage your iPhone. Here is a case. The iPhone 6 dropped into water, and then it won't turn on. After connect to DC power, it's current shows 480mA.Now, we need to know how to repair it.

Before you repair it, you need to prepared all the phone repair tools you needed. All of this you can find it in vipprogrammer.

 The following are the repair steps:

1. Measure PP_VCC_MAIN with multimeter, we found 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.

However, after we connect to power supply, the iPhone 6 still cannot be turned on. The current stops at 0.156A (156mA), as shown in picture 6-2.

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. 

3. Then we measure the AP_BI_I2C0_SDA and found it's voltage is 0V.This point is normal. The test point of signal AP_BI_I2C0_SDA in bitmap is shown in picture 6-4. 

4. 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 circuitdiagram is shown in picture 6-5.

5. After checking the circuit topography, we know that AP_BI_I2C0_SDA bus runs to U0201, U1202, U1700, U1501 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 picture 6-6.

6. Remove the 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.

7. 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 6-7.

8. 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 6-8.

  

Finally, after replace the D1501, everything goes fine, the iPhone 6 can be turn on and the it can be displayed normally, all the function back to normal. The iPhone was back to health.

6 steps to fix the iPhone 6S cannot turn on after water damaged

When your iPhone 6S accidently dropped into water, then shows dark screen and cannot turn on. Do you need to buy a new phone? No! There is a better idea here. Fix it!

1. Disassemble the iPhone 6S, we can found that the motherboard’s large area is water damaged. There are bumps on the upper board of CPU. After measuring, we find that the power supply of upper board is not short circuit. Connect the iPhone 6S to DC powersupply, the standby current shows about 0.24A, as shown in picture 1.

 

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2. Use multimeter to measure the diode data of PP_VCC_MAIN, the diode data is small,only several tens. After observing, we found that the capacitor near Wi-Fi chip darkens badly. Its material object is shown in picture 2.

 

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3. Remove the damaged capacitor and now the diode data of PP_VCC_MAIN is more than 100mA. As the water-damaged area is large, after observing carefully, we find that a capacitor at audio IC darkens badly too. Its material object is shown in picture 3.

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4. Remove it and now the diode data of PP_VCC_MAIN is more than 300mA.Connect DC power supply and the standby current becomes more than 30mA.Each power supply circuit is not short circuit. We can feel that the upper part of the circuits is hot when plugging power supply. Thus, put rosin at upper part of the circuits and wait it melt slowly, finding that the rosin at circuits of display screen power melts faster than other parts. The location of display power chip in bitmap is shown in picture 4. 

 

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5. Tear down the display screen power chip and connect power supply. The standby current recovers to normal 0, as shown in picture 5.

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6. Replace display screen power and the IC recover. Finally, iPhone 6S can boot normally and can back to normal work.

SOLVED: iPhone 6S current unstable and then died

The iPhone 6S accidently dropped into water and then pick it up, make it dry. After a while, we turn it on, the screen flashed then it turns black and can't turn on anymore.

Solution

1. Test the current. Connect iPhone 6S to DC power supply, check the current, it shows leakage 60mA, when we press the boot button, it shows 120mA then jump to 0mA,in the end, it repeats the jump process.

2. Tear down the CPU and shield cover of baseband. We can find that it have four eroded places, they are backlight power supply chip U4020, display power supply chip U4000, charging management chip U2300 and small audio chip U3700.

3. Clean the motherboard, then connect to DC power supply, the leakage current is getting smaller, about 20mA.After turning on, 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 1. The I2C0 bus in bitmap is shown in picture 2. The material object of I2C0 bus is shown in picture 3.

4. Cut the power and use digital multimer to measure the diode data of the I2C bus, there are 404 and 430 which is normal. Viewing the eroded components photos, our preliminary judgment is that the display chip U4000 damaged, because the backlight chip is painted with glue, which is not easy to be damaged, so we remove it.

5. After removing the display chip U4000, energize it, but 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.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 4.

6. Use multimeter to measure the diode data of R4020, we find that it is short circuit. Remove the backlight chip U4020 and energize motherboard to turn it on. The current jumps to 1A. After assembling backlight chip U4020 and display chip(VC468) U4000, the white Apple logo appears and iPhone gets into IOS normally. The iPhone 6S have wake up and can back to normal work.

Tips

1. As for the water-damaged iPhones, usually need take photos first for the watered places and then clean the motherboard. That will be beneficial, because if we find some problems during the repair process, we can refer to those photos to exclude badly eroded components.

2. The backlight chip DWI bus has SDI and SCK two signals. By measuring the diode data to ground, we can know whether backlight chip U4020 is workable or not. SCK can be measured at the resistor R4020 in picture 5-59 and SDI can be measured at the test point PP1002 in picture 5.

3. When dealing with the problems about the turn on failure after being watered, we can ignore the removed chips if they do not affect the turn on process. If the current jumps normally, we reassemble them.

SOLVED: iPhone 6S Plus cannot turn on after expand the NAND Flash

The lack of memory on the phone is very annoying, when you want to take photos, it this time your phone will jump out the tips which about the storage space is not enough, it make you very depressed. So, replace or expand the NAND Flash of the iPhone is a god idea. However, things don't turn out the way you want, after replace the NAND Flash, the iPhone dead. So, let's fix it.

Connect adjustable DCpower supply to test and the current reached 100mA when press power button to turn it on. But 2s later, current drops to 0mA.

This problem happens after enlarging NAND Flash Storage, so we first check whether there are any explosive tin balls around CPU. Remove the shield cover and find some unobvious bumps on the upper board of CPU. Observing under microscope, there are no explosive tin balls around CPU.

Directly short connect the power supply PP3V0_NAND of NAND to ground to force it enter DFU mode. Check whether iPhone can connect to WLAN (many motherboard whose current drops will not drop any current when it enters DFU mode).

 

Plug power supply and charging connector. Use tweezers to short connect non-grounding end of capacitor C1501 at the circuits of NAND Flash power supply PP3V0_NAND to the surface of NAND (The surface of all grey chips are connected to ground), and then plug USB cable. When power supply meter shows about 700mA~1A, loosen the tweezers. If the working condition is satisfied, i4 assistance on computer will remind that it enter DFU mode. If root iPhone right now, it is certain to report error 4005. The capacitor C1501 in bitmap is shown in picture 1. The capacitor C1501 and NAND power supply PP3V0_NAND in circuit diagram  are shown in picture 2.

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We enter DFU mode is just to judge whether the CPU working condition is normal and whether the lower board of CPU is normal.

When this motherboard enter DFU mode, it can connect to WLAN. According the experience, when blow NAND, the air gun blow the CPU upper board up causing the damage or pseudo soldering. Slightly heat motherboard for 1h and remove the CPU upper board (control the temperature). Then cool it and energizing it. The current now can reach 80mA. Therefore, we can be sure that it is the problem of CPU upper board. Replace the CPU upper board and iPhone can be turned on. The iPhone is coming back to life.