Professional Cell Phone Repair Guide

A seriously damaged iPhone 6 was obtained. After confirming with the customer, we knew that there was no iCloud backup on the phone. It will not turn on now. We judged the motherboard to be damaged, so we would have a iPhone 6 motherboard repair. How to recover data from dead phone or even dead motherboard? 1. First of all, opening the iPhone 6 and remove the motherboard off carefully 2. Desolder the A8 CPU , EEPROM and NAND Flash from motherboard with QUICK 861DW hot air gun . Note: you have to handle the 3 chips very carefully or data recovery will not be successful! 3. Use rosin, BGA paste flux, PCB cleaner, soldering iron and razor blade to clean the 3 chips. 4. Reballing the chips with iPhone BGA reballing stencil . 5. Put the new motherboard on iPhone 6 PCB holder and remore the A8 CPU, NAND Flash, EEPROM from it. 6. Install the 3 chips removed from broken motherboard to the new one。 7. Now finally we can assemble and install the iPhone 6 to have a test, data recover...

The loudspeaker does not play the music when turn music on, and there is no sound on the phone when it is called. How should we fix it? Let's test and repair in this article! First check whether ReMMI is in the headset mode. After checking, Redmi has no headphone mode, but speakers and mobile phones are still not working. Disassemble the Xiaomi Redmi by phone opening tools, use digital multimeter to measure the EAR_DET voltage, after measurement, there is no voltage and it is short circuit， R1904 is short circuit. Using precision titanium alloy tweezers to remove R194, it is found that capacitor DCDHSSHDEET is short circuited. Check Redmi schematic diagram , we know that CDC_HS_DET leads to a Redmi power supply IC. Test the Redmi, we find the power supply IC is overheat, replace the new Redmi power supply IC . Now find a 2.2K (222 capacitor), and then replace the R1904 capacitor, use QUICK 861DW hot air rework station to solder it with jump wire. Welding ReMMI...

A iPad AIR 2 was received, and the customer said he could use it yesterday, but today he suddenly failed to turn on the phone. How can we deal with this situation correctly? Let's have a look in this article! First, we connect the iPad to the computer to see if it is in the mode. If we enter the mode, we can restore the machine. After the connection, the computer was found in the recovery mode, but there was no serial number. It seems that the NAND flash chip was not recognized. Generally speaking, there are two kinds of faults: one is the NAND chip, the other is the circuit disconnecting CPU and NAND. This is easier to deal with, remove the iPad Air2 NAND chip, nothing is abnormal when we use Fluke digital multimeter to measure the grounding resistance of the NAND pad, that we judge it may be the problem of the NAND chip. Remove the NAND chip off and put it on iPad NAND Test Fixture , it can't be read so we can judge that the NAND chip has problem . Replace the NAND ch...

We are going to repair iPhone 6 with display failure, we get to know from customer that the situation happens after the battery was replaced. Why this happens? How should we test and repair? The iPhone 6 works normally before the battery is replaced, but the iPhone is not displayed after the battery is replaced. This fault is usually due to the client accidentally installing the long screw in the short screw position and then the screw under the circuit. It was pierced. Opening the iPhone and remove off the iPhone motherboard. Measure the resistance value to grounding for display socket J2019 with Fluke 15B+ Digital Multimeter , we find the resistance value to grounding for 14 pin AP_TO_LCM_RESET_CONN_L is infinitely large, which is clearly disconnected. There is the trace of a breakdown for left screw column BS2502 after observing it under the HDMI Camera Stereo Zoom Microscope , scrap it and re-connect the disconnection. Measure the resistance value to grounding for...

We are going to repair the iPhone 7 today, according to the customer's description, the main fault described is that it can enter the system and the message voice can also be heard, but the iPhone screen does not show anything. The black screen is as shown in picture 1. First of all, we need to have a test first, connect the adjustable DC power supply , the current shows all normal, and it also respond when connect it to the computer. Disassemble the iPhone 7 motherboard to measure the basic conditions of the display function by Fluke digital multimeter , it's measured that the seventh pin PP_1V8 of  touch socket(J4502) display power supply at infinite value, now the fault is found. The power supply is changed from PP_1V8 to PP1V8_LCM_CONN by inductor FL3906 conversion. The end of the inductor has resistance value, and the other end has no value, so we judge it's FL3906 damage. Connect the jumper wire as shown in picture 3. Failure is repaired successf...

When iPhone 7 restarts automatically, the white apple logo appears on the iPhone display, it can't enter the iOS system and the iPhone can flash, but the second time, iPhone 7 automatically restarts, and the flash memory process is not completed. The iPhone 7 originally needed to repair the audio part because it could not be recorded and could not send voice at WeChat or WhatsApp. For this audio failure, we can fix it by replacing the new iPhone audio. However, after replace the iPhone audio , the iPhone 7 always white Apple reboot. First we thought maybe it's the iPhone audio is not installed well, so we re-install the audio by QUICK 861DW  hot air rework station, but after replacement, the problem is the same. We try to flash the iPhone, the flash process runs smoothly, but it won't be able to access the IOS system after the flash, re-flash the iPhone again, the iPhone automatically restarts. Is the iPhone battery out of power? Replace the new iPhone battery , and ...

Got a apple 6S from one of our customers, the phone is stuck on white apple logo when turning it on, sometimes it turn into black screen. Why this situation appears? Let's have a look in this article! Try to enter iTunes mode online, we are not able to enter iTunes data cable mode but DFU mode,which can be online, and we can confirm that it has nothing to do with U2 fault. There is automatic black screen after the white apple appears. The computer prompt can not jump from DFU to recovery mode. This is often caused by iPhone NAND or CPU. The power supply of the iPhone 6s can be measured according to the WUXINJI schematic diagram . The two 1.8V are on C1534 and C1560 respectively, 0.9V is on C1548, and 3.0V is on C1502, and the NAND voltage is normal. You need to take down the pin resistance of the NAND to see if there is a break between the CPU and the NAND chip. At the same time, you need to test whether the NAND itself is damaged. The protective measures should be pre heat...