Detail Way for Repair iPhone 7P Boot Failure

According to our ever experience, the fault related with boot failure, usually it was caused by the control IC. 

Anyway, we need to test the current and voltage, then get the final result.

First step we need to connect it to DC power supply with iPhone lightning cable to test the iPhone charging current, the current jumps around 200 mA, not stable. The computer can't identify the iPhone when it is connected, and it doesn't boot.

Nest we need to disassemble iPhone to detect. Use phone opening tools to tear down the iPhone, and then remove the iPhone motherboard. Measure the iPhone motherboard with Fluke 15B+ Digital Multimeter, there is no current, which means no leakage. Trigger it and it shows large current, the current up to 1.9A. Now, apply some rosin on iPhone logic board, and then use QUICK 861DW hot air rework station to heat it, it's turning white.

Picture 17-8-1

It's frustrating to see this, did the iPhone main power break down? Open the WUXINJI Dongle to check iPhone bitmap, we found the iPhone Nand flash power also was in the hot spot, first we need to measure the iPhone Nand flash to check if it is short circuit. After measurement, the iPhone Nand flash is short circuit.

 

Picture 17-8-2 

Now, scrape out the iPhone Nand flash around the tape of the power supply large capacitor, and then apply rosin on it, adjust the ammeter to 3 V and heating this circuit by QUICK 861DW hot air rework station, this capacitor is short circuit, remove it.

17-8-3

After finishing the last step, we test it again, get the normal current and voltage value, boot it,  the phone back to normal.

Check iPhone 6S Plus No Service Fault Carefully

While the no service fault always along with the SIM card, at the same time, SIM card along with the signal part and REFF bus, so we need to find the sources fault. 

Obviously, we need to check it carefully, cuz it ask a disassemble. Following the steps:

Plug SIM card in, we can see the serial number when dial *#06# on dialing interface, as shown in 17-7-1, it seems that it is not the problem of the REFF bus, so we can exclude the fault caused by the bus (if the bus caused the fault, it will not show the serial number on the iPhone 6s Plus screen after dialing the *#06#).

Picture 17-7-1

From picture 17-7-2, we can see the operator option on the interface, there seems to be no problem with the receiving section. The problem is in the launch section.

Remove the iPhone 6s Plus logic board and measure by Fluke digital multimeter, we found the resistance value of PP_1V0_LDO9 was only 47, which was supplied to U_WTR_RF RF IC.

Remove the U_WTR_RF RF IC to measure again, the ground resistance value returns to normal.

Replace a new iPhone 6s Plus RF IC, install to have a test.

Conclusion: the fault was caused by U_WTR_RF RF IC.

We just need to remove it, we will note it, how about you?

Error Code 14 On iPhone 6S Plus iTunes

Usually the error code will match with the corresponding deal way.  

As for the error 14, we doubt there happens some fault on Phone NAND flash. What we got the iPhone 6S Plus reports the fault error 14, so we need to handle it carefully.

Anyway, we still need to flash it , connect iPhone to computer with lightning cable, use iTunes to flash iPhone, the iTunes reports that the iPhone "iPhone" could not be restored. An unknown error occurred (14).

Disassemble the iPhone, take out the iPhone motherboard, and then carefully remove the iPhone Nand flash. Check iPhone bitmap on WUXINJI Dongle, and then measure the diode data with multimeter, we found that the resistance value of iPhone Nand flash solder pad M6 Pin is infinitely large.

Picture 1

This pin passes through the R1501 resistor and pulls down, there is no resistance value when measured it with Fluke 15B+ Digital Multimeter, now we're judging that the R1501 resistor is damaged.

Use QUICK 861DW hot air rework station and tweezers to replace the R1501 resistor, and then measure the resistance value of iPhone Nand flash solder pad M6 Pin again, the data is normal.

Picture 2

Install the iPhone Nand flash to iPhone motherboard, now the flash is finished successfully. The iPhone 6S Plus fault has been repaired.

How to check iPhone 6 boot fault?

Don't be panic when your iPhone 6 can't boot, most of this case was caused by  control IC. But as the fault was caused because of the secondary fault, so we need to pay more attention on this guy.

First of all, check the bus and reset, both of them are normal. Cut the shiled cover above the fingerprint, use Fluke 15B+ digital multimeter to measure the resistance of CPU to the clock and data.

The normal values of R0317 and R0316 are more than 400, the measurement of R0317 resistance is 745, and the R0316 is 479. This case is mostly the two pin of AP31 and AR31 in the right lower right corner of CPU has pseudo soldering. First press the iPhone 6 CPU to test whether the device can turn on or not, do not try to reflash the phone first, it will report error 9. Of course, the best method for CPU pseudo soldering is redo the parts, here we try a method of jumper wire connection without removing CPU necessary (6 and 6P can be common used).

As shown in picture 17-1-1, look at the position of the two points on the wuxinji schematic diagram, the lower right corner is 0, the width is 1.45MM (the width of 4 solder joints), the height is 1.75MM (the height of the 7 solder joints), which can be slightly shaved on this basis, first probably draw a rectangle. When the upper cover is very hard, do not use brute force, select a sharp phone repair blade, you should slow down when finish scraping on the white pad from cover to the CPU upper cover, after scraping the white pad, the point we are looking for will come out, the wire on the CPU chip must be operated under the HDMI Camera microscope.

picture 17-1-1

First test the resistance of the two points. If normal, smear green oil on the top (except for the two points we are going to connect jumper wire). After the curing we can connect jumper wire, use QUICK TR1300A hot air gun to blow very small tin balls on the 2 points respectively , we choose to use the wire of the receiver, it's thinner, the receiver wire is with glue, scrape the 2 ends and apply a little solder. As shown in picture 17-1-2.

Picture 17-1-2

Use jumper wire on the corresponding two points separately. ( it's better to do on both two points to avoid rework repair). Once you finish flying, just apply the green oil and use UV light for curing.

Like we predicted, the fault happens on IC, if you can finish the soldering rework by yourself,  you may can try to the continued steps.

DIY Solution for iPhone 7 Charging Error

Fault Description: iPhone 7 happens charging fault while control IC was replaced ever.

According to the attached file, we doubt there may happen fault on the phone control IC, so we need to disassemble it, get the PCB board ,with the diagnostic tool to check it.

The iPhone 7 USB control IC damage will cause charging and online failure, prompting unrecognized USB and no support for this accessory, it may also cause a failure to stuck on white Apple logo while turning on the iPhone.

How do we repair the charging fault? it can be solved by the short connection, we can check the iPhone 7 charging part schematic diagram by WUXINJI dongle as shown in picture 1-1, the detailed repair steps are as following:

picture 1-1

1.Plug in data cable and use Fluke 15B+ Digital Multimeter to measure whether the PP5V0_USB of point A has a 5V.

If not, check and replace the iPhone 7 charging port flex cable.

If there is 5V, continue to see if there is 5V at the point B.

2. As shown in picure 1-2, continue to measure the 5V voltage with multimeter.

picture 1-2

If not, it indicates that the charging protection tube is damaged, which can be short connected as shown in the picture.

3. If both point A and point B have 5V, replace the charger IC and USB control IC.

If you are interested in DIY, maybe you can check it by yourself, with a microscope along with the LED light, then you can try to fix it by yourself.

Solution for iPhone 6S Plus display and touch fault

While you happens some screen fault, you may be craze about this fault. At least, i can't stand it.

Fortunatelly, i have learnt some phone repair knowledge, then i can fix it by myself, then it also can be useful for doing a phone repair business.

iPhone 6S plus touch IC is on the touch screen, so there no need extra operation for phone motherboard, it will be easier for the next repair procedure.

By checking WUXINJI schematic diagram, we can see that the power supply of the display and touch screen is supplied by U4000 and power C--U2000.

The power IC provides a 1.8V power supply, and U4000 provides 5.7V to 5.1V voltage. As shown in picture 1-1.

 picture 1-1

The inductor FL4200 FL4205 FL4207 FL4208 FL4209 FL4210 is easy to corrode, resulting in no indication, no touch. If you encounter the same condition, short connection can solve the problem.

If there is no light and no display, first you need to do is to install the iPhone 6s plus screen (Since it is more troublesome to install screen for measurement, you can also short connect by jumper wire as the green line remarked in picture 1-2, then use Fluke 15B+ digital multimeter to measure the IC output voltage 5.7V on single logic board directly.

picture 1-2

If there is no 5.7V on the components as shown in picture 1-3, it means that the display screen power supply IC--U4000 is damaged, the solution is to to replace a new U4000. If there is 5.7V, you need to check the short inductance FL4200 FL4205 FL4207. If there is touch failure condition, check and short connect FL4208 FL4209 FL4210.

picture 1-3

While doing the corresponding deal as followed our guiding, you will get the right result.

Solution for iPhone 7P Charging Fault

Most of iPhone 7P charging fault are related with the charging port, or the phone battery, if you don't know how to fix the charging fault, just directly replacing it. If it still keeps invalid, you may need to find a phone repair shop.

Charging station ask a disassemble, along with the professional skill, so you may be interested what we will shared.

Check iPhone schematic diagram on WUXINJI Dongle, 5V charge voltage PP5V0_USB  sent by the tail-plug interface，one circuit is sent to iPhone charge IC, one circuit is sent to iPhone USB control IC. The repair method is as follows.

Disassemble the iPhone 7 Plus with phone disassemble kits, remove the iPhone motherboard.

Measure the 5.0V voltage (PP5V0_USB) next to the iPhone charging IC with
Fluke 15B+ Digital Multimeter to check whether it exists. If not, then you need to replace the new iPhone tail plug flex cable. If yes, continue to check.

Measure the 5.0V voltage (PP5V0_USB) next to the iPhone USB control IC with multimeter to check whether it exists. If not, then you need to use QUICK 861DW hot air rework station to solder the jump wire from 5.0V voltage (PP5V0_USB) next to the iPhone charging IC to 5.0V voltage (PP5V0_USB) next to the iPhone USB control IC. If 5V is exist， then you need to replace the iPhone USB control IC and iPhone charge IC.

If you don't have enough tools to repair it,  maybe you can borrow it from your friends, or purchase it on online shopping WEB.

Two solution for iPhone 5SE Circuit Fault

Fault description: iPhone 5SE occurred turning on fault and leakage.
Possibility reason: phone CPU problem or battery short circuit.

According to our ever experience, we doubt there mostly exist circuit problem, which means we need to disassemble it and check the current by DC power supply, like the following PIC shown:

picture 1-1

The battery positive voltage VBATT is first sent to the charging IC-U2300, and the charging IC-U2300 outputs the main power supply VCC_MAIN (same as the battery positive voltage value) to the main power supply U2000 and other related circuits.

The situation is divided into the following:

1. The current is large when supplying power, this situation is usually caused by the positive voltage of the battery or the main power supply, which has short circuited parts. The large current can be quickly found with the rosin method. How to operate: At first, use digital multi-meter to measure the battery positive pole and the main power supply to the ground resistance value, find out the short circuit parts. Use rosin to smoke the iPhone SE main board into white color, add voltage in the short circuit parts, you have to notice that the voltage must be added to the short circuit parts, the voltage is gradually increased from zero, after the short circuited parts is supplied power for a while, it will heat and turn into different color, then you can find the specific components immediately.

2. The iPhone SE device has no response after turning on, first measure whether the main power supply of U2300 is there, if not, you need to replace U2300, if the main power supply is normal, then it means the problem is from the power IC or CPU.

3. The current is small and iPhone is unavailable, measuring whether the voltage of the parts as shown in WUXINJI schematic diagram is normal, as shown in 1-2, if yes, you need to replace the clock crystal Y0600, check and weld several pull resistance of bus circuit will cause small current and iPhone unavailable, these resistance must be replaced instead of short connection, if the above problems are excluded, it should be the iPhone SE CPU  problem, you can install a new CPU to solve.

Picture 1-2

How to handle iPad Air2 Reboot Fault while Blurred Screen

Fault description: iPad Air2 happens blurred screen while reboot automatically

Repair iPad will be easier than iPhone, as of its body, don't ask too precision tool. But most of us will choose to purchase a new one to replace the older,  because the price of iPad are sold cheaper than iPhone device.

While the repair fee also are cheaper, it is okay, we need to fix it firstly.

Connect the iPad 2 on computer and reflash by iTunes, it reports error 4013, we judge the problem comes from flash memory.

Use corresponding iPad opening toolkit to disssaemble the iPad Air2 and take off the motherboard, then put the motherboard on iPad PCB test fixture for the next repair operation. It is found the iPad NAND chip was repaired before, so we remove the Nand chip and reflash again, the error code is reported again. So we are going to directly repair flash memory.

After the flash memory is installed, it's normal when reflashing again, invalid SN is reported.

If the invalid SN is reported, it basically means flash memory has no problem, install the iPad Air2 NAND chip and turn it on directly.

Generally, blurred screen and reboot is caused by the flash memory problem, if you encounter the similar problems in the future, directly repair flash memory.

This NAND chip was repaired before, so we estimate the flash memory is false welded when blowing with hot air gun. In the past, the customers who had iPad Air 2 NAND flash memory expansion said that it did not take long to encounter new problem. So you need to be very careful on iPad Air2. The NAND flash is very close to CPU flash , the last repairman was prying from the inside when expanding NAND flash memory, we usually cut the shield from the outside and pry from the outside, this will be more safe.

iPhone 6S button fault as of IC problem

More use, easier fault. Fortunately, it is just a little part, no worry about it.

According to the topic, you may have known what we will talked. Got this phone, just like spending out lunch time normally, we have met so many fault like this. Ok, let us prepare our tool to fix it.

Put iPhone 6S on the WL Aluminum Alloy Pad, and then use phone opening tools to disassemble the iPhone, take out the iPhone motherboard.

Measure the resistance of J4700_3# with Fluke 15B+ Digital Multimeter, it is normal. Put iPhone motherboard under the 3.5X-90X Stereo Zoom Microscope to check, we found the iPhone power IC was replaced by other phone repair man. Measure its voltage, it only has 0.5V, and the voltage of BUTTON_VOL_UP_CONN_L volume up button signal is pulled down. 

16-11-1

Based on our repair experience, mostly this failure is caused by damaged iPhone CPU, so replace the iPhone power IC is useless. 

BUTTON_VOL_UP_L lower voltage, it has no external pull resistance, it is pulled directly through the CPU internal. Borrow PP3V0_TRISTARUSB controller 3V string the resistance of 1K, so that the voltage is pulled up to 1.6V. 

Assemble the iPhone to test; now the iPhone volume up button can be used normally.

16-11-2

Fix iPhone 6 with Professional Phone Repair Tool

Got the problem iPhone 6, we knew it was much intractability as it was described many faults occurred, like battery, charging IC and  PCB motherboard .

We doubt there seems to happen a secondary damaged, if it was just repaired for one time, it won't happen so many fault.  Then we have got it, we should be responsible for it, with out professional phone repair tool to fix it, cure it, keeping your step in our tutorial.

1. Use a Fluke digital multimeter to measure the voltage of (C1408, C1700) USB were given to U1401 charge tube and U1700 (U2), the both 5V are normal

2. Respectively remove the U2 and charge tube, measure the bottom voltage to see whether the iPhone 6 motherboard has broken cables, the result shows that the two chips are all normal.

3. Replace the two new chips and charge to have a test, the result is same.

4. Connect the iPhone 6 with computer, the battery life shows no data on Ace assistant, this situation often happens on iPhone 6 and iPhone 6P, basically it's caused by the problem of CPU to the charge tube battery detection circuit, also the solutions are different.

5. By checking 2.2K resistance(remove R0302 and R0303 from junk motherboard) on WUXINJI schematic diagram, then connect the two resistors together. One end receives the main power supply, and the other end is grounded, and solder a jumper wire to charge tube G1 pin in the middele of the two resistors.

6. Personally, I think this method is troublesome, there is another simple way to use: add a 10K resistance (R0307 or R0310) on C1700(next to U2), which can be directly welded to one end of the C1700 PP3.0V, the other end can be welded to the charge tube G1 pin, then use green oil and UV light to solid.

7. Install the iPhone 6 device to test, charging function is normal now.

That is all the detail process, if you are interested in DIY, maybe you can try to do it by yourself, any tools needs pls contact us.

Handle iPhone 6S Touch Panel Fault Effectively

In some case, we try our best to avoid repairing again. But we can't refuse what we received,  customer is God. But as a professional repair man, no matter what met, we also need to check it carefully, to avoid this phenomenon happens again.

We got a iPhone 6S, question Phone, from one of our client. They DIY it by himself, but it seems the process didn't get a good result. Okay, let us start it.

Following the detail fix process:

Disassemble the iPhone by phone opening tools, remove the iPhone motherboard, and then measure the diode data for iPhone touch screen with Fluke 15B+ Digital Multimeter, we found the iPhone touch screen synchronized pin is short circuit. A capacitive filter on the side of the socket, a capacitor directly connect to CPU, we can check iPhone schematic diagram on WUXINJI Dongle.

Now, we need to remove the capacitor with Precision Titanium Alloy Tweezers, after movement, measure it again, it still is short circuit. Now, we need to remove inductance,

Use QUICK 861DW hot air rework station to remove the inductance, and then measure it again with multimeter, short circuit phenomenon still exists.

The socket is short circuit, the capacitor is short circuit, and the inductance also is short circuit, we can't fix it by borrowing power from other place.

So there just existing one way to fix it, dangling touch, we test it and found it can work normally, it is amazing, thanks for our ever experience.