iPhone 7 Plus no service error – Fix iPhone baseband CPU

 When iPhone 7 Plus is turned on, but it can't make the phone calls, becasue the iPhone 7P has no service.  After check the iPhone, we found it is iPhone baseband CPU porblem, we can fix it. 

Check iPhone 7 Plus again,  dialing the *#06#, there are no IMEI appears on iPhone display screen. Check Settings on iPhone, there are IM and Modem Firmware numbers. After reset the iPhone network settings,  the problem still there.

Open the WUXINJI Dongle, and then compare with the iPhone schematic diagram and iPhone motherboard bitmap to measure the iPhone circuit line power supply. After measurement, all power supply on the iPhone baseband power tested are normal, we need to re-install the iPhone baseband CPU.

Because it is very close to main CPU, we need to do a heating insulation for the CPU. Use QUICK 861DW hot air rework station to heat iPhone CPU for a while, and then use BGA graver to gently remove the glue. We can remove the inductor on the right side fist and then insert the blade, or we can insert the blade in the slot，we'd better choose the thin blade. When heated it with hot air gun, we blow from the side of the CPU to the card slot. When we need to pay it, we can select a component around the baseband as a reference, and when the tin of reference begins to melt, we can start to pry into the baseband.

There are many empty on the iPhone baseband CPU, observe it under the Stereo Zoom Microscope, and then compare it with iPhone bitmap, there are many pins missing. Apply some lower temperature solder paste on the solder pad, and then soldering the iPhone baseband CPU with solder paste and glue, install it to the iPhone motherboard. After the iPhone motherboard is cooled, use digital multimeter to test whether the peripheral components short-circuit, so you can determine whether the chip has been installed intact.

Install the iPhone 7 Plus, turn on iPhone, now the signal is back, the service is normal.

Solved: iPhone 7 Plus compass abnormal issue

A customer sent us an iPhone 7 Plus need to be repaired, the problem is that the iPhone 7 Plus compass not working, it is abnormal. 

After we received the iPhone 7 Plus, get into IOS to test the iPhone compass function, it doesn't work.

Disassemble the iPhone 7 Plus by phone opening tools, take out the iPhone motherboard. The appearance of iPhone motherboard looks good, but there are traces of moldy around the gyroscope.

Carefully clean up the moldy areas, and then connect it to DC power supply, it boots normally. Install the iPhone, and test it, everything is fine, except the compass.

For this case, some people will think it's the compass problem, and it can be fixed by replacing the new compass; some people will think that the gyroscope is virtual welded, because the gyroscope is moldy, it can be fixed by reballing the gyroscope.

We need to observe the iPhone motherboard. Put it under the Stereo Zoom Microscope to observe the compass and gyroscope, the parts around the compass are good, but one of the 0 Ohm resistors around the gyroscope is slightly corroded, and two inductors ware also slightly corroded near the display socket.

Touch it with tweezers, it fell off easily. We need to short connect them. Use QUICK 861DW hot air rework station to solder the jump wire, and then clear it up.

Install the iPhone and test it, the compass functions works properly, the problem has been solved!

Guide: iPhone dead motherboard data recovery

Here is the guide for iPhone data recovery from iPhone dead motherboard. We got the iPhone 6 need to be repair, the problem is that the iPhone motherbaord is damaged, and the iPhone won't turn on anymore, but we need to recover the data from the dead iPhone motherboard. 

First, disassemble the iPhone by phone opening tools, and then take out the iPhone motherboard.



Desolder the A8 CPU, EEPROM and NAND Flash from motherboard with QUICK 861DW hot air gun.

Use rosin, BGA paste flux, PCB cleaner, soldering iron and razor blade to clean the 3 chips.

Reballing the chips with iPhone BGA reballing stencil.

Put the new motherboard on iPhone 6 PCB holder and remore the A8 CPU, NAND Flash, EEPROM from it.

Install the 3 chips removed from broken motherboard to the new one by QUICK 861DW hot air rework station.

Assemble the iPhone and check whether the data has been recovered.

Note: 

Please handle these 3 chips very carefully to keep them safe. 

How to fix iPhone 6 black screen/WIFI/volume button failures?

The iPhone 6 has black screen, WIFI cannot be recognized, volume button not working issues after replace the iPhone display screen, how to fix?

Disassemble the iPhone by phone opening tools, and then remove the iPhone motherboard.

Meassure the diode data for display socket J2019 with Fluke 15B+ Digital Multimeter, we find the diode data for 14 pin AP_TO_LCM_RESET_CONN_L is infinitely large, which is disconnected.

Put iPhone motherboard under the Stereo Zoom Microscope to check , we can see that there is the trace of a breakdown for left screw column BS2502,  scrap it and re-connect the disconnection. Measure the resistance value to grounding for display socket J2019 14 pin AP_TO_LCM_RESET_CONN_L with multimeter, the data is normal.

Install the iPhone and test it, we find the iPhone volume button not working, and the WIFI cannot be recognized.

Measure the resistance value to grounding for iPhone volume button socket J0802, it is infinitely large, and perhaps it is disconnection. This circuit line is on the third floor of the left screw column that near the edge position, carefully scrape it and then re-connect it.

There are 2 reasons causes the WIFI cannot be recognized, one is the iPhone motherboard disconnection, and the other one is iPhone WIFI module IC problem. Remove the iPhone WIFI module IC and measure the resistance value to grounding for solder pad, no abnormal was found. Replace the new iPhone WIFI module IC, and then measure it agian, seems all data are normal now.

Finally, install the iPhone and turn on iPhone 6 to test, the iPhone display screen works fine,  test the iPhone volume button, it works properly, test iPhone WIFI, also works good. All failures has been fixed, the iPhone 6 back to normal work.

Dropped iPhone 6 no fingerprint—How to fix ?

A dropped iPhone，the iPhone display screen has been replaced, after using for a while, the customer feedback that the fingerprint unlock function can't be used. Check fingerprint on the Settings, it prompts that "Failed, Unable to complete touch ID setup, please go back and try again".

Use Fluke 15B+ Digital Multimeter to measure the resistance value for fingerprint socket, all is normal. Replace the fingerprint connector flex cable, we found a tear mark on the iPhone fingerprint button.

Perhaps the iPhone fingerprint can't be used is caused by disconnection, we need to re-connect the new flex cable. The line inside the flex cable is very thin, total is 19 lines. This can't connect a single cable, we can only remove the flex cable to docking.

Take a new iPhone home button, put it under the Stereo Zoom Microscope, cut off from the position close to the original iPhone home button disconnection, take the end of the socket (try to cut a bit longer), we can separate the lines and lid on the original home button, there is a solder point, directly heated with the QUCIK 861DW hot air rework station, and then pry it with the blade.

After separating the iPhone home button, we can cut off the fingerprint from the disconnection place, scraping fingerprint cable must be very careful, pay attention to the direction cannot be blown back

We've better find some bad home button and then scrap the flex cable to practice, the boot flex cable can also be practiced.

After scraping，apply some tin on it, and then connect the new and old iPhone fingerprint flex cable.

After finish the connection, first we need to test it, if the test is successful, we can reinforce it. Cut off a small piece of discarded fingerprint flex cable, use glue to cover the docking area for protection. After the glue has solidified, install the iPhone and test it again. The iPhone 6 no fingerprint failure repairing done!