Professional Cell Phone Repair Guide

As the matter of computer system software, when rooting, different computer may have different circumstances. After receiving iPhone and rooting it, I find that when the progress bar goes about one tenth, as shown in the following picture, it reports error (40). Judging from my repair 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 the picture. Use JC NAND FLASH Test Fixture  to test NAND FLASH, finding no series number in NAND FLASH, as shown in the following picture. Thus I know that the NAND FLASH is damaged. I am goint to replace NAND FLASH. As the series number is stored inside NAND FLASH, at the same time, I 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. The method...

We will fix an iPad Air 2 with the fault like this: it cannot be charged before replacing its USB management chip , after the problem is sloved and assembling it, we find that it gets into IOS and sometimes screen turns red and roots itself. As the USB management chip was replaced before, we worry about that the USB management chip is damaged or the solder is worse, so here we replace the chip again. But the problem remains the same, which suggests that USB management chip is workable. Next we use the smallest peripherals method to exclude the faulty places. Unplug all the connection cable from other peripherals to motherboard, such as camera , sensitization, as shown in the picture. 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. Judging from my repair experience, after excluding the peripherals pro...

We received an iPad 4 with unknown error (9) when rooted by iTunes, the picture is as following Judging from my repair experience, if it reports unknown error (9), NAND FLASH power supply or NAND FLASH  itself is damaged. First measure each power supply of NAND FLASH. They are normal. Next, remove NAND FLASH and deal with the solder tin  and black glue, as shown in the picture. Assemble the removed NAND FLASH on a workable motherboard  to root. It still reports unknown error (9). I can be sure that the NAND FLASH is faulty. Put new NAND FLASH on NAND FLASH testing jig to find out the information and series number. The software operation interface of NAND test fixture  is shown in picture. Then solder the NAND FLASH with information and series number and on motherboard, as shown in the picture. Connect computer to root, as shown in the picture. It is activated and gets into IOS system normally, as shown in the picture. Test all the functions. The...

It's very common that backlight module will be damaged after cell phone dropping into water, in this case, the screen will diplays abnormally. The phenomenon is just like the iPhone 5s screen in the following picture. As for those iPhones whose backlight module is damaged after water gets in, replacing screen assembly  can settle the problem but that will cost too much. Customers will find it hard to accept it. If you can master the way to replace the backlight module, you can save much from for you customers. The tools and assistance materials are 530 cleanser, non-dust cloth, backlight module, Electric Soldering Iron and pre-heater platform, as shown in the picture. First use electric Soldering iron to burn out the backlight module power supply circuit, as shown in picture. Set preheater to 80℃ to soften the glue around the backlight module so that it is easy to separate them, as shown in picture. Use non-dust cloth  to dip 530 cleanser to clean the dus...

The iPhone 6 is burned out when charging, it still can't work after repaired. We can see from the picure, the iPhone 6 motherboard pins drop very seriously! And most of the components on the motherboard are removed so that results the phone cannot work well. For those motherboard  whose pins drops seriously, I have to replace it with other workable motherboard. That is to say, remove all the major parts to other workable motherboard. Find a iPhone 6 motherboard in the picture. Remove all the chips and tin them. First solder main power supply , USB charge management chip , charge field tube, NAND Flash and CPU and so on, as shown in the following. Then turn it on and it can display normally, as shown in the picture. The previous parts are soldered normally. Next I continue to remove the small parts. After removing all the parts. Turn it on and get into IOS to test. All the functions are normal. “about iPhone” can display all the serial number, as shown in the...

How to tear down iPhone 7 in a proper way without more damage to your device? There are detailed operation if you want to repair your cell phone. Hope it will help you!  Step 1 Prepare iPhone 7 device and necessary  opening toolkit . Eject the Nano-SIM card tray, remove the two bottom 3.4 mm Pentalobe screws. Use the triangle opening tool slice through the sticky adhesive and carefully separate the iPhone 7 display assembly on the rear case.  Don' t remove it entirely as the display assembly is still connected to the iPhone by cables along the middle-right side. Step 2  Remove the following 4 Tri-Point  screws  securing the bracket that covers the battery connector and two of the display cables.  Remove the following 2 Phillips screws that secure the bracket covering the upper component display cable. Disconnect the cable and free the iPhone 7 display assembly from the phone. Step 3 Remove the following 6 Phillips screws, followed by the metal cli...

Have you ever met the same situation? It's really annoying that screen gets blurry after cell phone being wet. Here we will solve it step by step on how to fix blurry screen on water damaged iPhone 6. Tear the cell phone down and remove the battery . I still found some water in it and waterproof label is discolored. After cleaning the obvious water, I find that the area around the screw hole at the corner of motherboard  is eroded. Remove the shield cover  and find that one end of resistor has white tin while the other turns black, which is obviously eroded. Checking the bitmap, I know that the number of this resistor is R0706. Open circuit diagram and search R0706 to find its location. It is a 1k pull-up resistor starting from CPU to front camera' s I2C bus clock signal. Remove the resistor from the same place at accessories pad and solder it on the faulty motherboard. Turn it on and the problem disappears. I have to remind every reader that if this kin...

We received the iPhone 6 motherboard from one of our customers. We find that the rear housing is damaged, but it can be used normally. After replacing the back housing, we notices there is no firmware version in cell phone.  How to solve the problem?  We save the teardown process as the customer sends the motherboard. Observing from the side face, I find that the board bends. Combining the description from customer, we presume that the baseband or the baseband power supply is pseudo soldering. Energizing it and turn it on to test the power supply. VREG_SMPS2_1V25, VREG_SMPS3_0V95 and VREG_SMPS4_2V075 are normal. Only VREG_SMPS1_0V90 has no voltage. The circuit diagram of these voltages is shown in the picture. The test points of VREG_SMPS2_1V25, VREG_SMPS3_0V95 and VREG_SMPS4_2V075 in bitmap are shown in the picture. They are all measured at the inductors around the baseband. The material objects of VREG_SMPS2_1V25, VREG_SMPS3_0V95 and VREG_SMPS4_2V075 are shown in t...

In the past days, we received a client 's wet iPhone 6s plus, he mentioned the backlight was not working after cell phone dropped into water, after that, he fixed it well. However, the rear camera  gots some trouble again, The 2.8V chip was replaced already. Simple operation first, tear down iPhone and replace the rear camera subassembly. When we are going to replace it, we are surprised to find that some components near the camera socket J3200 are eroded. After checking the circuit diagram , we find that three inductors are missing. The three inductors in bitmap are shown in yellow points in the picture. Their material objects are shown in the picture. In real repair cases, we directly short connect the two ends of the inductor to speed up. After the whole iPhone is fixed, we find other workable inductor to assemble. After short connecting the two ends of the inductor, measure the diode data to ground of its socket. The data is normal. We think it recovers now. So we a...

Have you ever met the same phenomenon for iPhone? One of our customer consulted us the fault of his iPhone 6, it is dropped on floor by accident, luckily, it can be turned on and also work well at the moment. However, the screen turns white and the iPhone often reboot automatically when charging or only be used for a while. For this problem, we decide to offer some solution. After measuring, we find that CPU is pseudo soldering. We have to remove CPU and remount it. First remove CPU and clean the exposed copper on its solder pad. Use UV Solder Resist to paint the exposed copper and use UV ultraviolet Light Lamp to solidify it. At the bottom right corner, there are missing joints. One of them is the pin to fingerprint EEPOM. Press the pin with multimeter and there is diode data if we press hard. Thus, we know that the board is disconnected. Doing Jump wire from the solder pad. Solder CPU and jump the wire to fingerprint EEPOM The fingerprint EEPOM at motherboard is...

There is a bad connection for wires with circuit board screws, nothing displayed on screen after iPhone turning on. Our client mentioned his iPhone 6 the problem remains same though it is repaired before.  How to fix motherboard broken wires to get normal work? First we tear it down and find three screws  are twisted deeply. The problems are no backlight, no display and no ±5.7V power supply of screen. Observing under microscope , we find that the four circuits under those screws are disconnected. One of the four circuits is the open signal LCM_TO_CHESTNUT_PWR_EN of display power supply chip . This signal connects power supply chip U1202. The signal LCM_TO_CHESTNUT_PWR_EN connects display power supply chip U1501 The signal LCM_TO_CHESTNUT_PWR_EN connects display socket J2019 through the inductor FL2035 After measuring, display socket has no diode data, which suggests that it is disconnected. We have to jump a wire. After it can display, we measure o...