跳至主要内容

Guide: iPhone 6 LCD Screen Display Problem


Received an iPhone 6, the fault was that the iPhone sometimes display normally, but sometimes not. Open iPhone 6 to test, iPhone LCD display does not show anything. Removing the iPhone motherboard and looking under a stereo zoom microscope, it was found that there was a lot of solder paste in the socket of the iPhone monitor and the socket of the iPhone touch.

Is that the socket not clean? First we use BGA clean water to clean the iPhone motherboard, after cleaning, we can use digital multimeter to measure the grounding resistance value for the J2019 display socket 1 pin PP_LCM_BL_CAT2_CONN and 4 pin PP_LCM_BL_CAT1_CONN, these two pins will cause iPhone screen half bright and half black problem. We found the resistance value of 4 pin is 2111, which is abnormal, the normal resistance value is about 570.

After short connection of the FL2025 fuse inductor, the resistance tested is normal.


Assemble the iPhone display screen and test it, the Apple logo can be displayed normally, but the backlight still not bright. We noticed that the CPU shield cover was been moved, remove the CPU shield cover, we found the CPU was been repaired. Now, it's easy to explain, the U1502 backlight IC is virtual welded when blowing the CPU by QUICK 861DW hot air rework station, and it leads the iPhone LCD screen sometimes bright and sometimes not. Also, there are many solder paste and tin balls, which is easy cause iPhone motherboard to short circuit.


Clean up the tin balls and solder paste, and then remove the iPhone backlight IC. There is a good way to remove the iPhone backlight IC, remove the three filter capacitors above the backlight IC, and then the iPhone backlight IC is easy to remove.


Reballing tin and then install the chip, assemble the iPhone and test it, the fault has been solved.

If you want to get more cell phone repair tutorials, just contact us on www.vipfixphone.com

评论

发表评论

此博客中的热门博文

iPhone 6 Display Failure after Replacing LCD

The iPhone 6 display is black after replacing LCD. After checking, the diode data of display socket is normal and all power supply for iPhone display IC  output is normal. Testing by  DC power supply , we find the iPhone current is abnormal. When press the iPhone power button, the boot current is obviously large. The current reached 100mA when press the power button. After remove the display tube, the current still the same, which means there is a short circuit. Measure the voltage output of each circuit of power supply with Fluke 15B+ Digital Multimeter , then surprised to find that there are really short circuit places. LD010 is short circuit; we suspect that the filter capacitance on the circuit has been penetrated. After remove the iPhone power control IC , we found it is ground short circuit. Open the WUXINJI Dongle  to check the iPhone schematic circuit, we found that this circuit is the display card image transmission MIPI data bus power supply. CPU brea...
发表评论
阅读全文

Solution: iPhone X Won't Turn On

According to the customer's description, the iPhone X would not turn on after it drop accidentally. Then the cell phone reports error 56 when restore it. How did this happen? Let's test and repair step by step. Since iPhone X motherboard 2 layers are connected through the middle column, the solder points are very easy to get dropped. so we guess that the solder points from NFC chip to the CPU part have fell off. Disassemble the iPhone X by iPhone opening tools , remove the upper board off the main board, when separate the main board we see there is a row of points have fell off. Check the location map on WUXINJI dongle , it is surrounded by a ground wire, in fact, there are 6 useful points dropped. The ground wire does not need to be filled, the 6 useful points are added by professional phone welding tools. These are the signal wires of the NFC chip, so the iPhone X would report error 56. Then the tin of the middle column is repaired by iPhone X BGA reballing ste...
发表评论
阅读全文

Guide: iPhone 7 Plus Camera Fault Repair

iPhone camera failure is common for most of cell phone repair technicians, today, we're going to fix iPhone 7 Plus camera. According to the holder's description, the front small camera is normal while the rear camera fails to take photos, when turn on it, the iPhone 7 shows black screen. Let's start from easy repair operation: directly replace the iPhone camera to have a test.  Note: Pay attention that two camera are connected together. When disassemble the iPhone 7P rear camera , you need to pry up from the left side.  The fault is same as before after replacing a new rear camera. We tested before, the iPhone 7P double camera is rely on the bigger camera to get image, as shown in 15-5-1, the corresponding part on iPhone 7P motherboard is J4501 pin, the resistance value is normal after testing with Fluke 15B+ digital multimeter , it reminds of us that iPhone6 Plus also encountered this phenomenon, the power supply part has some problem. By checking on  WUXINJ...
3 条评论
阅读全文