How to recover display screen touch function on iPhone 6

The display screen touch function was broken, there is no response when we touch the iPhone screen.  This situation happens after fixing the broken screws on motherboard.

What do we do to restore iPhone 6 touch function.

Power on iPhone 6 and test it, the touch screen has no response and there is no white stripes. In this situation, the generally black touch IC does not work or CPU can't recognize the Touch screen control IC. According the trouble phenomenon there could be disconnect. After disassemble the iPhone 6, we can find that the iPhone has been repaired, and it's more serious. As shown in picture 1.

First use digital oscilloscope to measure touch IC, it shows 5.1V, 5.7V, and also has the voltage of black touch ic. This result indicates that both the white and black touch IC all is working, probably it's a sync signal problem, check it with schematic diagram. As shown in picture 2/3/4/5

From display interface to backlight test point and CPU , and then to black touch ic and synchronous circuit, on this line, as long as there is a bad chip, it will lead to no sync signal.  After measure the chips, we find that from the backlight IC to U2403 was disconnected, put it under the stereo microscope, and then we directly solder jump wire. As shown in picture 6, 

After solder jump wire, assemble the iPhone 6 and power on, and then test it, touch function has been restored, as shown in picture 7. The trouble has been solved.

Best solution for iPhone 6 Plus won't boot and shows unknown error 9

Why the iPhone 6 Plus cannot turn on? Why it shows unknown error 9 when root it? Are you still looking for a solution? This article can solve your troubles.

Usually, if iPhone cannot turn on, we will try to solve the problem by rooting it first. In this case, the iPhone 6 Plus fell, and then it didn't boot. When we use iTunes to root iPhone 6 Plus, it reports unknown error 9. According our experience, the unknown error 9 was caused by NAND Flash error of CPU error. We need to explore the cause of it further and solve the problem.

First, remove NAND FLASH and use multimeter to measure the diode data to ground, finding them normal. I suppose that the NAND FLASH itself is damaged. After I replacing a new one, the problem remains the same, so NAND FLASH is excluded.

Second, check CPU. As for dropped iPhone 6 or iPhone 6 Plus, the solder pad that CPU uses it to connect logic eeprom chip is easy to drop joints. Remove logic chip to measure the diode data. The location of logic chip is shown in picture 7-32.

 

Then we measure the diode data to ground of the solder pad, finding that the data is infinite. Thus, we can be sure that CPU is pseudo soldering. After removing CPU, I find that the some of CPU pins connected with logic chip are gone, as shown in picture 7-33.

After fixing the upper and lower board of CPU, jump two wires from solder pad to logic board. The picture of soldered CPU is not clear, but we can see the jumped wires and UV Solder Resist, as shown in picture 7-34.

After jumping wires and soldering CPU, turn iPhone on and get into IOS, as shown in picture 7-35. The unknown error 9 is missing, and the iPhone 6 Plus can back to normal work.

SOLVED: iPad Air 2 shows red screen and then restart automatically

The iPad Air 2 cannot be charged, so we replace the new USB management chip, the charging went back normal. However, after assembling it, we found that it sometimes can get into IOS and sometimes screen turns red and then roots itself. We need to fix it.

Because we changed the USB management chip, then we worry about that the USB management chip is damaged or the solder is worse, so we replace the chip again. But the problem remains the same, this means the problem is not related to the USB management chip.

Then we unplug all the connection cable from other peripherals to motherboard to troubleshoot the problem, such as camera, sensitization, as shown in picture 7-14.

Put the single motherboard with display flex cable on electric tester. After unplugging all peripherals and testing many times, the problem remains the same, which suggests that the problem is unrelated with peripherals.

According our experience, after excluding the peripherals problems, damaged NAND FLASH and pseudo soldering could cause iPad red screen. The biggest possibility is that these two chips, CPU and NAND FLASH. We replaced the NAND Flash first, The motherboard without NAND FLASH is shown in picture 7-15. But after soldering NAND FLASH again, the problems still the same. So we re-solder CPU and test, the problem was solved, and the iPad back to normal work.

Repair guide for iPhone 5S shows unknown error 40 when restore IOS

There are many iTunes error code, each error code has different meaning, it means there's something wrong with your iPhone. Today, we will share how to fix iTunes error 40 on iPhone 5S. When we restore the IOS firmware of iPhone 5S, it failed and shows iTunes error 40.

Different computer may have different circumstances when root it, this is because of computer system software and other issues. We root iPhone 5S again, we found that when the progress bar goes about one tenth, as shown in picture 7-16, it reports error 40. 

 

As our experience, when the progress bar goes about one tenth, it reports error 40, which may be related to NAND FLASH. Next, remove motherboard and pry up NAND FLASH, as shown in picture 7-17.

 

Then, use JC NANDFLASH Test Fixture to test NAND FLASH, finding no series number in NAND FLASH, as shown in picture 7-18. Thus we know that the NAND FLASH was damaged.

 

Next, we need to replace the new NAND flash, as the series number is stored inside NAND FLASH, at the same time; we have to replace the series number too. Because the original NAND FLASH is damaged, I cannot know the series number from original NAND FLASH, so I have to search the series number through original motherboard IMEI.

Finally, after writing the series number, we root again and the rooting goes smoothly. The IOS of iPhone 5S can be update restore now.

Note:

The method of getting motherboard IMEI without touch any chips:

Remove a NAND FLASH from a workable motherboard and assemble it on the faulty motherboard to root. When the activation interface is shown, clicking the icon that resembles exclamation mark, we can see the IMEI. Now I can search the series number through original motherboard IMEI and write series number into the workable NAND FLASH, the operation interface is shown in picture 7-19.