Solve iPhone 7 can't turn on after water damaged

Free repair for our customer as he is our VIP customer. His iPhone 7 dropped into water which lead to the iPhone power button out of work. We doubt the motherboard occurred short circuit, Following the measures we take:

After disassemble the iPhone by JM-9102 Disassemble Tools, we can see the mist in the iPhone, so we need to handle the mist first. After it is done, measure the iPhone with DC power supply, apply some power on iPhone, and then press the Power-on button to check the boot current, it shows large current.

According to the current situation, this phenomenon should be the load of the power supply is short circuit. Now, we immediately use a method of feeling temperature to check, we found the lower part of the iPhone was hot. To narrow the scope, we can use the method of solder rosin to check, we found that one of the reserve capacitors in the light boost circuit was shorted.

With the help of YH898D hot air gun and Titanium Alloy Tweezers, we remove this capacitor, and then test it again, the current returns to normal.

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However, the iPhone screen still no lights, sometimes we can see a little faint light. Using Fluke 15B+ Digital Multimeter to measure the voltage of lighting, it instantly shows 11V, then immediately turns 2.4V, sometimes turns 5V, and the voltage is very unstable. At this time, we know there's a problem with the lighting booster circuit.

Observing the iPhone motherboard under a VGA Camera 7-45X Trinocular Stereo Microscope, we found a glass-diode crack in the booster circuit. May be the user in the iPhone after the water, power on it and test, because of the continuously working, the diode is burned.

 

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After replacing the new diode, the iPhone lights are back to normal, which means the iPhone touch screen can be display now!  

Summary: The repairing of mobile phones is not only a theory, but also a variety of methods, such as Temperature-sensing method, Solder rosin method, and Microscope observation method, etc.

Fix iPhone 6 Microphone Earphone Speakers No Sound

As for this fault is controlled by many chips, so we should take some professional tools to fix it to avoid more malfunction. And it has ringtone sound while someone calls, but the speaker icon turns grey after connection, as shown in picture 12--5-1:

First, we use the simplest elimination method to diagnose where the fault comes from, removing the iPhone 6 charging flex cable to check the receiver; removing the earphone to test the speaker. After testing, there is still no voice. It can be judged that the chip is out of order.

The iPhone 6 U0900 big audio damage directly caused the 3 voice failure, it's relatively simple to disassemble and assemble large audio chip, layer welding spot is large while the iPhone audio chip is big and thin, so it's necessary to avoid excessive force to crush the chip during solder reballing process. Replace U0900 chip, all sound tests OK. U0900 position is shown in picture 12-5-2.

U1601 small audio water damaged phone comes out of a lot of problems, leading to large current, and there will be an automatic phone speaker. If the reset signal given by the iPhone CPU is abnormal, we can scrape and weld a jumper wire from the bottom of the chassis A6 track.

If the sound off and on, you can remove a small audio chip, when there is a temperature, measure the resistance value of the U1601 A6 track by digital multimeter. as show in 12-5-3:

iPhone 6 will also have a headphone mode, which automatically enters the headset mode without the plug in the headset.

The J1817 tail plug can be tested. If the block is normal, it will be solved by replacing the tail plug flex cable.

If there is the absence of a single sound instead of 3, we can replace the new parts, detect the circuit or test the block value, then basically you can find the problem.

   

Solve iPhone 6 No Display After Boot

Got the iPhone 6 which needs to repair iPhone 6 LCD screen ,according to the attached file, we knew the phone has no display after boot. Still we need to adhere three steps to fix it.

Measure the diode data of display socket J2019 with Fluke 15B+ Digital Multimeter, there is no exception found in data. Measure the power supply output of iPhone display touch IC, there is no short circuit. When measuring the bootstrap voltage, we found there is no voltage. 

We can check the iPhone circuit schematic diagram on WUXINJI Dongle

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When we measure diode data, we found that C1554 had no short circuit, but also no resistance. In normal case, C1554-1 this one end can measure more than 600, the reverse resistance C1554-2 this one end can be measured to more than 600. We initially suspected that the display IC is virtual welding, after replanting the tin with QUICK 861DW Hot Air Rework Station, it doesn't work. Now, our suspicions are disconnected. Remove the display touch IC, and then measure the display touch IC C4# pin and E4# pin to the C1554 these two lines, all is disconnected.

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C1554 on the back, the distance of the welding jump wire is far. In view of aesthetic, so we directly weld the jump wire near the display touch IC C4 # pin and the E4 pin.

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After that, install the iPhone 6 and test it, the iPhone touch screen is displayed properly now!

Way to Repair iPhone 6P Reboot Failure

Got the touch screen failure iPhone 6P, the first step we need to do is to check the voltage and current .

Following the detail way:

For this kind of repaired device, we need to first check the place that moved before. Connect DC power supply it does not leak, the starting current stays on more than 400 mA. As shown in picture 12-3-1.

Considering the touch IC has been replaced, the last repairman directly took the black touch off without welding jumper wire on touch M1 pin(6P can still boot normally without installing black and white touch), but the current is same as before, measuring the starting voltage we find the iPhone 6 Plus NAND1.8V and I2C bus 0.6 V, so we doubt it is the iPhone power IC problem. With the power on, it is indeed hot, with 400 degrees we quickly take the power IC off, according to the symptom, it's necessary to confirm whether the power supply IC is damaged, a good method is to measure the pin resistance.

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The results of this 6P is measured as the power of IC to 1.8V white touch power supply is short-circuit, now it can be judged that 1.8V power supply short circuit pulled down the power of NAND and bus, removing the white touch chip, short circuit fault is solved now, welding jumper wire on black touch M1 and replace new chip, the iPhone 6 Plus is successfully fixed here.

  

Handle iPhone 6 overheating and can't boot

We got a cellphone which is Japanese style, it means all of the words shows japanese.

It lead to some inconvenience for our repair,  but we still need to analysis the fault:

1 iPhone 6 battery consumption fast and overheating

2 Wi-Fi and bluetooth appears unstable

3 Can't go into IOS now.

And the Japan clients said the iPhone battery  was replaced ever.

Following the repair process:

Comprehensive information provided by customer, we think this is caused by the damage to the iPhone WiFi chip. The iPhone can be powered on before, but not boot now, mostly because the batteries are running out.

Using JM-9102 Disassemble Tools to dismantle the iPhone, test the battery, it's really running out of power. Just leave it alone first，and supply power on the iPhone motherboard.

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As shown above picture, it's leaking 200mA. Now measure the diode data of VCC_MAIN with Fluke 15B+ Digital Multimeter, as shown in the following picture

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 Judging from the test results, the diode data of VCC_MAIN is low. Think of the customer before said WiFi sometimes good sometimes bad, so we directly remove the iPhone WIFI IC.

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 After removing the WIFI chip, measure it again, now the diode data of VCC_MAIN is back to normal. Using DC power supply to provide the power to iPhone motherboard to test.

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The iPhone standby current is normal, no more leakage. Find new WiFi chip and install it, the boot current also normal. Directly assemble the iPhone, the charging current has 1A, which means the previous judgment is correct. After booting, the WIFI and Bluetooth are available.

Fix iPhone 6 Can't Store Photos

When your phone can't  continue store photos, maybe many of our readers think the  iPhone 6 motherboard  caused this.

But we should test then get the conclusion,like the picture showed, we found the screw column was damaged .

This screwdriver has a flashing light on the back of the camera. According to our repair experience, it is known that photos cannot be saved should be the iPhone flash IC problem. Will it be caused by screwdriver column? So after measuring the camera, the EN signal was found to be in a normal state, and would it be a semi - connected state?

After scraping, it is found that this line is nearly disconnected. Is it the problem here? The photo is really not saved after installing to test. Connect the line, the fault finally comes out.

Next, removing the flash IC off and cleaning the glue of the weld plate, then we start to measure the resistance, he E2 pin of the flash lamp is found to have no resistance. This is the I2C bus that connects the iPhone 6 CPU with the rear camera and the flash IC. The details are shown in WUXINJI schematic diagram.

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Scraping the lead to get rid of the possibility of broken line.

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The camera can get the resistance and get the exclusion of CPU false welding, it should be disconnected line problem in the plate. The solution is to connect jumper wire  from the E2 pin of the flash IC to the rear camera socket FL2329. As shown in Picture 12-1-5.

After welding the jumper wire, the flashing light E2 has a resistance value, install the flash lamp IC back, fault is solved now!

Work iPhone 6 Abnormal Touch Failure out

We get the iphone 6 which occurred touch function don't work normally. When we boot it and enter the IOS, the iPhone shows normal ,but no effect while you touch it with your fingertips. Finger on the iPhone display screen, 

we get the same result. So we got it and need to fix it well.

Testing it by disassemble the iPhone, we found the white touch IC and black touch IC has been replaced. Because the phone has been repaired many times, although not repaired, but these two chips have been replaced, which means that they are normal. And then we according to the fingers with a little force can slide to judge the line that from black touch IC to touch socket and touch socket itself are good. Because if they are abnormal, either the display screen will appear with a vertical bar or the touch is completely unavailable. Either lack of transverse or lack of vertical, but in the actual test did not find a lack of transverse or lack of vertical phenomenon, so the above judgments is correct.

And then according the above phenomenon, we judged the circuit line that from iPhone CPU to white touch IC also normal, so we decided to repair it starting from these two chips peripheral circuits. Use Fluke 15B+ Digital Multimeter to measure the black touch IC +-5.7V voltage and 1.8V voltage, all is normal. Measuring the white touch IC 5.1V and 1.8V, also is normal. Then we think it would be more precise to use the Hantek DSO1060 oscilloscope to measure, but the result of the oscilloscope measurement is normal. There is no idea now, we open the WUXINJI circuit diagram and analyze it, see if we can find out the reason and solution.

After checking the WUXINJI circuit diagram, seems find nothing. But we see a bias capacitor C2439 on the black touch circuit, and then think of the iPhone that was repaired, which the audio have sound, but the sound is small or very light fault, all of these failures are repaired by replacing the audio bias capacitor next to the iPhone audio IC. Will this touch faulty be caused by this bias capacitor?

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Measure the diode data of other ungrounded ends first, we found that it's about the same as the normal board, but we still decided replace it with new one. Then we remove a same capacitor from damaged motherboard, and install it with QUICK 861DW soldering station. The result is that the fault is perfectly repaired.