How to fix iPhone 6s won't turn on after water damaged

As we all know, the importance of cellphone to people, so it's unfortunate that the phone drop into water, and it won't turned on. I hope these things don't happen to you, but if you are going through this, this article will help you.

1. Tear down the iPhone and connect the motherboard with adjustable power. Let it standby but there is no current. We can be sure that the main power supply is not short circuit. Triggering it on, the current changes to 50mA and then it is power fail, but goes back to 50mA again automatically. It repeats the former process again and again.

2. If the output voltage from iPhone 6S power chip is short circuit, the chip will get into the protection mode. Therefore we measure the diode data to ground of CPU upper cover, finding no short circuit. Then we measure the diode data to ground of each power supply, as shown in picture 5-1. We find the diode data to ground of EEPROM P3V0_NAND is 0, which is short circuit.

 

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3. The test point of P3V0_NAND in bitmap is shown in picture 5-2. The material object is shown in picture 5-3.

 

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4. Observing under microscope, we find that one end of a capacitor is black and eroded, as shown in picture 5-4.

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5. Checking iPhone bitmap , we find the location of the capacitor is C1503, as shown in picture 5-5, which is the filter capacitor supplying power to EEPROM. The circuit diagram of C1503 is shown in picture 5-6.

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Finally, after tearing the capacitor, the diode data to ground of EEPROM P3V0_NAND turns normal. Trigger it on and enter IOS normally. The iPhone can back to normal work.

Here's the short guide for iPhone 6s black screen and power button not working

There are many fans of APPLE, iPhone is popular to peoples. The iPhone 6s have many advantages, but as you use the iPhone, you'll find a lot of problems. Such as the iPhone 6s screen turns black and after a while it is no response when press power button. Generally, it should be turn on when press the power button. i think , there are many people are troubled by this issue. So, we wrote a guide for fix this problem.

First, turn on iPhone and enter IOS to test all these functions. The screen turns black after standby time lasts a little longer, which may be caused by faulty functional chips and interrupt signal of power. After functional test, we find that the compass cannot be used while other functions are normal.

Second, tear iPhone down and observe motherboard, finding that the compass has been soldered and other chips are not soldered. Fix the compass and other problems may be settled if the compass is fixed. The material object is shown in picture 1-1.Remove the compass and measure the diode data of the below pins (picture 1-2). All the data is normal.

 

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Third, turn on the single motherboard and measure the 3.3V power supply of PP3V0_TRISTAR and 1.8V power supply of PP1V8_IMU_OWL, and they are normal. The testing points are shown in picture 1-3.

 

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Fourth, with normal power supply, we replace the compass chip. After replacing the chip, enter IOS to test and problems remain the same as before. Therefore, we guess that the problem may be related to SPI bus used to communicate with CPU. The compass, accelerator, gyroscope and these sensor chips of the series before iPhone 6s are managed by co-processor, such as the M8 of iPhone 6, the M7 of iPhone 5S. IPhone 6S and iPhone 6S Plus have removed co-processor and leave the work to CPU.

Fifth, remove the chips that are connected with SPI bus of compass chip. These chips are baroceptor U3020, accelerator U3010 and gyroscope U3030. As the baroceptor is close to EEPROM, we can remove it without tearing the shield cover. The location of baroceptor is shown in picture 1-4.

 

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Finally, after removing the baroceptor chip, the result is still the same. Next replace an accelerator to test compass which is now workable, so is the gyroscope. Turn on iPhone to standby for half an hour and then turn on screen. The screen can be turned on normally and the issue has been solved.

How to fix iPhone flashlight won't turn on

Last week, a customer sent a iPhone 6 to me, because the iPhone 6 flashlight not working, he has been send this iPhone6 to other place for repair, after checking, After checking, there was a line that got into CPU short connected and CPU was broken. And the maintenance personnel can't fix it. So the customers sent it to our technical, and hope we can fix it. Let's see what's going on this phone

First, turn it on and get into IOS to open torch, finding that the flashlight cannot be turn on. After removing motheboard, we find that there is no flashlight chip. Observing under microscope, we can see that some pins are missing on solder pad of flashlight chip. The location of solder pad is shown in picture 1-1. Then we call the customer and know that the previous maintenance personnel do not assemble the flashlight chip after tearing it down

 

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Second, after counting under microscope, we know there are 8 pins missing. Previous maintenance personnel might worry about that high temperature would damage the CPU, so he violently pry up the chip. Through schematic diagram, we know that the missing pins are earth wire, LED1 power supply and the pin used to auto-lift the voltage of flashlight chip, as shown in picture 1-2.The flashlight chip is burnt because the pin used to auto-lift the voltage of flashlight chip is dropped.

 

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Third, solder these pins under microscope and use BGA solder paste  to solidify them. Assemble flashlight chip, as shown in picture 1-3.

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Finally, turn on iPhone and get into IOS to open flashlight. The LED can be opened normally. The iPhone can back to normal work.

How to fix unworkable compass on iPhone 6

One day, i want to go hiking, and then i need to prepare something for the journey. One thing is compass, so i turn on my compass of my iPhone6, but i found that it doesn't turn, just like stuck. So, i find the technical of Vipprog, and he fix it. I wrote down the solution, and just for in case, it can help you.

First, we measure whether the power supply of compass control chip is normal. Through circuit diagram, we know that compass control chip U1901 requires the power supply from PP3V0_IMU and PP1V8_OSCAR, as shown in picture 1-1.

 

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Second, check the PCB bitmap,we know that the power supply of PP3V0_IMU and PP1V8_OSCAR can be measured at C1902 and C1901 near U1901, as shown in picture 1-2. The material object of capacitors C1902 and C1901 is shown in picture 1-3. Energizing iPhone, measure the voltages and they are normal. Replace the compass control chip and measure again. The problem is still the same.

 

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Third, use multimeter to measure the diode data to ground of four circuits of SPI bus that communicates with compass control chip. With the normal power supply  and bus and the replaced chip, we presume that other components cause the problem. Checking the circuit diagram again, we find that SPI bus connects co-processor U2201, gyroscope chip U2203, baroceptor U2204 and accelerator U2205, as shown in picture 1-4~7.

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Fourth, through schematic diagram, we know that any of the four chips on SPI bus, the other three chips will be affected through SPI bus. Open compass and turn iPhone. The pointer does not move, as shown in picture 1-8.

 

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Finally, Turn off iPhone and replace gyroscope chip U2203. The material object of U2203 is shown in picture 1-9.Then assemble iPhone and get into IOS to test. Gyroscope and compass function recovers. The iPhone return to health

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