Excellent solution for iPhone 6S home button not working

Customer sent an iPhone 6S to us, the fault phenomenon is that the iPhone home button is not sensitive and fail frequently. Get into IOS system to test it, the fingerprint function is normal. Sometimes the iPhone home button needs to be pressed several times before it can respond; we suspect there's a problem with the shrapnel button behind the fingerprint key.

Disassemble the iPhone by phone opening tools, then replace the fingerprint button and test it, now the home button function back to normal, so we exclude the iPhone motherboard error. Remove the waterproof adhesive covered by the shrapnel button, which is behind the fingerprint button. Put the multimeter on the corresponding pins, press the switch and test it, the data is normal, so we can eliminate the problem of the switch itself.

Put it under the phone repari microscope and observe it carefully, we found a rift in the edge of the line, pry the iron sheet off the power button, scrape the line, we can make sure it is disconnected. Solder the jump wire with phone rework station, this fault is resolved.

Before we pry the iron sheet, we need to clean up the solder tin in the red circle first by suction tin wire. If you don't clean it up, and directly pry it, it's easy to break the line again. Scrape the line with a sharp blade and gently scrape it, because the line is very thin, the blunt blade is easy to scrape off the line.

After the scrape, solder the tin on the pins. Find a thin copper wire and apply the tin, and then align them, heating the copper wire, finally you can fix it.

After soldering the jump wire, paint some green UV oil on it, fixed it with a UV lamp light, and then install the iron sheet in the same place. Welding the solder tin on the corner to fix it, and apply green UV oil to the edge position to fix the iron sheet. 

Repair iPhone 7 Plus issues: no service, black screen, unknown error 56

Today, we will share a repair guide for iPhone 7 Plus issues, this iPhone is severely corroded by water, it cause many problems, such as black screen, no service, unknown error 56 and so on. We need to fix it step by step, please be more patient on it!

Rip off the motherboard sticker that can be ripped, and remove the iPhone PCB shield cover that can be removed. According observe, we find the most serious is the display backlight part. Now we can clean the iPhone motherboard first, and then measuring power supply C3405 with multimeter, it directly to the ground, careful observation under the microscope found that C3722 was severely corroded. After removal, the diode data of the main power supply becomes 298. At this time, connect it to power and phone standby leakage 30mA, press the iPhone power button, the iPhone screen is lit, but the left screen is dark. Leave it alone, enter the IOS, and insert the SIM card to test, we find there is no 3G、4G， the fingerprint is normal. It not only stuck on fingerprint setting, but also the restore network, restore all settings. Observing it under the microscope, we found that FL3901 corrosion seriously caused the left iPhone backlight IC cannot supply power. After soldering jump wire, it's back to normal.

Then found R7109 corrosion damage caused the power supply to high-frequency power amplifier circuit impassability, resulting in no 3G and 4G.  After soldering jump wire with rework station, it's back to normal.

Now we're going to solve the problem that stuck on iPhone. We want to backup first and then brush iPhone, then we found it can connect to PC, but when you connect to iTunes, it times out, dis U2 cause it? So we replace it with iPhone 6S U2 IC, but the problem still exists. So now we directly use DFU mode to forced brush iPhone.

However, when the progress bar shows 60%, it reports unknown error 56, re-flash several times, it still the same, the unknown error 56 most caused by NFC. iPhone Baseband CPU、camera power supply could also cause the problem, but these function all is normal, so we judged NFC. Observing NFC under the microscope, we found that it had a little corrosion.

Remove the NFC, and measure the diode data of NFC, we found the G2, D5 and C7 all is connect to ground. From the phone circuit diagram, these three points are connected to the NFBST_RF, as shown in picture 10-2-2, we directly remove it, G2 still short circuit. After remove the C7517, the resistance is normal; D5 and C7 also back to normal. Replace the chips on motherboard, and weld well, flash it again, it still reports unknown error 56. Water-damaged motherboard power supply is the easiest to burn, so we remove shield cover of iPhone CPU.

It can be seen from the phone schematic diagram, there is a group of power supply PP_VDD_MAIN_NFC converted by NFCSW_RF which from main power supply, so we can weld the jump wire from the A1 pin to the A2 pin.

Finally, once again brush iPhone, you can enter the IOS system now! Test the functions, all is fine, the repairs end!

How to fix iPhone 6 cannot boot—need retain data

The iPhone 6 doesn't boot, and the boot current is 700mA. We need to fix it without delete the phone data.

Repair Process

1. Disassemble the iPhone by phone opening tools, take out the iPhone motherboard. Connect it to DC power supply, the boot current shows 700mA, which means there is a power supply short circuit.

2. Open the phonecircuit diagram and check it, we can find that the diode data of PP1V8_SDRAM is low.

3. Measure the diode data the PP1V8_SDRAM with multimeter, the data only have around 100, it is lower than normal data.

4. According to the repair experience, this group abnormal power supply was caused by damaged capacitor at lower right corner of iPhone CPU. As shown in picture 9-13-5. We directly pick it off.

5. After remove it, measure the diode data again, now the data is back to normal.

Finally, assemble the iPhone and test it, now it can be successfully powered on and smoothly into the IOS system.

iPhone 6s no display? The best solution is here!

The iPhone 6s accidentally drop into ground, we pick it up and turn it on, the iPhone screen shows black, it just no display. However, it can receive the phone call. We need best solution for this issue!

Disassemble the iPhone; take out the iPhone battery and supply power to it with DC power supply, the current is normal. Remove the iPhone screen, and then install the test screen, power on it and test it, the screen can display normally and appear white Apple interface. We thought the screen was damaged by dropping, but when we plug the original screen, it also can be light up, so we can exclude screen problem. 

The device light up, there are some problems when we are waiting to enter the IOS interface, blurry screen, grey screen, black screen, and it then cannot be wake up. Unplug the power and reboot iPhone, but the problems still exists.

Determine the fault is in the display section, remove the iPhone motherboard, use multimeter to measure the diode date of display socket, the data of all signal and power supply is normal. Reinsert screen and boot it, the white Apple still can be display, but after about 10 seconds, the screen suddenly turn into dark.

Unplug the power plug and screen test socket, measure the diode data on it, we found that the diode data of two pins on backlight is abnormal, one is more than 300, one is more than 700, the normal data of both pins should be around 600, as shown in picture 9-11-2. After a while, the data is normal, the data of these two pins also is normal in the first time, so we judged the faulty probably in the backlight part, so we replace the backlight IC. We can check it under the microscope.

After replace the iPhonebacklight IC, the boot process without any abnormalities, it can directly into the IOS. 

Finally, we input the boot password and test all functions, everything is fine. The iPhone 6s has been repaired!

iPhone 6S issues: 2G No service and vibration not working

Trouble Phenomenon

 

The iPhone 6s fell into the water, the signal is good, but it can't make the phone call; 2G signal shows no service; the vibration function cannot be used.

Repair process

1. Power on iPhone, and test it, it has 3G and 4G signal, 2G signal is abnormal, it has no service.

2. Disassemble the iPhone 6s, take out the motherboard, and then connect it to DC power supply, we found it leaking 13mA, the water cell phone 2g signal is not normal. To observe a passing element under a VGA Digital Microscope, we found the R4501_RF resistance on 2G PA U2GPA_RF has been moldy, as shown in picture 9-9-1. Touch it lightly with tweezers, it fell down. The PP_VCC_MAIN through it supply power to U2GPA_RF, so it caused the 2G signal to be abnormal. Clean it up and weld it with solderingstation. After finish it, boot it and test it, the 2G signal is back to normal.

3. The vibration function of iPhone 6s is controlled by U3800 PA chip. Use multimeter to measure the diode data of tail socket, the result is normal. After we remove the U3800 PA chip, we found the solder pad is moldy, so we replace the U3800 PA chip, after that, no leakage when the phone is standby and the vibration function back to normal. The repairs end!