Solved: Water-Damaged iPhone 6S stuck on White Apple Logo after booting

The iPhone 6S fell into water, and then it stuck on white Apple logo after booting. It was repaired once before, when we received it, the iPhone 6S in white Apple status and it will be restarted occasionally. After remove the iPhone logic board, we found that the iPhone U2 IC and charge tube has been replaced.

Check the iPhone logic board under a 3.5X-90X Stereo Zoom Microscope 14MP HDMI Camera, there are small beads around the chip, which is a serious mistake. Clean up the iPhone logic board and then replace the new U2 IC and charge tube, but the problem still the same, iPhone stuck on white Apple logo and restart occasionally.

Use Fluke 15B+ Digital Multimeter to measure the diode data for iPhone battery detective pin, the data is normal, the resistance of iPhone booting condition is normal, and the voltage also is normal.

For the watered-iPhone, iPhone system is less damaged. After consulting with the customer, we start to flash iPhone. Connect iPhone to computer with iPhone lightning cable, the computer pop-up prompts that USB is not recognized. We suspect that the problem will be in the U2 circuit line. Take off the U2 to measure the resistance value.

After measurement, the U2 IC F4 pin PP3.0V_TRISTAR is short circuit, this point is connected to power and an inductor FL5408_RF next to an iPhone WIFI module IC, the U5411_RF receive amplifier is connected to the head of iPhone logic board. In order to find the problem point correctly, first we remove the FL5408_RF, measuring the ends of the inductor, we found a short circuit at the end of the amplifier.

 

Remove the two capacitors on the bottom, the problem still there. Remove the U5411 IC, and then measure it, the data is normal. The glue around this chip is very soft，use QUICK 861DW hot air rework station in 150 degree to remove it is enough, and please don't remove the capacitor next to it.

Finally, install the IC, re-weld the FL5408_RF, test iPhone and it can be turned on properly.

Solved: iPhone 6 won’t boot after LCD screen replacement

 The iPhone 6 LCD screen has some problem, so we replace it and then we try to turn on iPhone to test, after we press the iPhone power button, the iPhone 6 won't boot, it just stuck on white Apple logo and then auto restart.  We need to solved it.

  

According to repair experience, we need to check iPhone CPU part. Check the bus and reset first, 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.

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.

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 5V USB Ultra Violet Light Lamp for curing.

Now, meausre the iPhone 6 agian, the data is normal. Install the iPhone,and press the iPhone power button, now the iPhone 6 can be turned on smoothly. 

Solved: iPhone 6 Camera Not Working (can’t take pictures)

When you turn on camera on iPhone 6 to take photos, you found the iPhone rear camera not working, it can't take pictures. 

The J2321 is the interface of rear camera. After checking the iPhone 6 schematic diagram on WUXINJI Dongle, we know that there are 4 sets of power supply circuit; they go through inductance L2329, L2330, L2318, FL2343 to the rear camera interface J2321, where the PP2V85_RCAM_AVDD_CONN is 2.8V power supply! It is provided by the small glass ID-- U2301, when turn on the iPhone camera, the CAM_EXT_LDO_EN signal that sent from the iPhone CPU controls 2.8V voltage that output by U2301, and then after the inductor FL2343, send to the interface J2321.

No matter U2301 fell into water or ground, it is easy to damage, and then causes no 2.8V voltage; the final result is that the iPhone can't take pictures. For the damaged power supply tube, we can remove it directly. And the for the water damaged iPhone, the L2329, L2330, L2318, FL2343 is easy to corrode and cause not to take pictures, you can short connect it with QUICK 861DW hot air rework station and jump wire.

Also, the iPhone flash IC--U1602 has several data signal is share with camera (AP_TO_RCAM_I2C_SCL, AP_BI_RCAM_I2C_SDA), so, the short circuit iPhone flash IC -- U1602 also can cause iPhone won't take pictures.

The repair process for the iPhone camera can't take pictures is as follows:

1.       check the socket for corrosion, if yes, clean it and weld it

2.       check if inductance L2329, L2330, L2318 and FL2343 are open circuit, if yes, short connect it.

3.       check if C2303 has 2.8V when open the iPhone camera, if not, replace the new U2301, or you can remove it and short connect it.

4.       check if C2323 has 1.8V, C2389 has 1.2V, C2390 has 1.8V, if both of them is normal, and interface also weld well, then try to replace iPhone camera flash controlIC U1602. Moreover, this IC output the flash light control signal PP_STRB_DRIVER_TO_LED_COOL, PP?_STRB_DRIVER_TO_LED_WARM, after iPhone boot flex cable interface to flash IC LED. If the flash light not working properly, first you should check LED.

5.       Use Fluke 15B+ Digital Multimeter to measure the voltage of PP_VCC_MAIN on capacitor C1686 to check if it is normal, and check if L1605 is open circuit. If both of them is normal, but the fault is still exists, then you need to replace the U1602 flash IC.

iTunes Error 4013 Occurs On iPad Air 2—Best Solution

The iPad Air 2 reports iTunes error 4013, the details is that, we need to flash iPad Air 2, because the iPad Air 2 can't get into IOS. Connect iPad to computer with iPhone lightning cable, and the use latest iTunes to flash it,  after a while, iTunes Error 4013 Occurs On iPad Air 2.  Here is the best solution. 

According our experience, 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 NAND flash  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 QUICK 861DW hot air rework station.

After finish it, install the iPad and test it agian, now the flash process is successful, and the iPad get into IOS properly.