跳至主要内容

Solution: iPhone 5S Fails to Boot

Have you ever met iPhone 5s booting failure? There are several situations for iPhone 5S booting failure. Before repairing, you need to observe and test the damaged part first.


1. large current value

Use DC power supply to have a test, If iPhone 5S has large power current and fails to boot, it is often caused by one of the circuit from PP_BATT_VCC or PP_VCC_MAIN is short-circuit, the solution is same as the power leakage repair.

2.No power leakage when power off, large current when press power button

This situation is a short-circuit of the output of the power IC. Measure the ground resistance of each output of the power IC with Fluke 15B+ Digital Multimeter , and find out where the short-circuit part is. Then replace it.

3. Booting with 50 Ma Current

Most of this fault is caused by the iPhone 5S CPU or NAND is damaged, repair will be very difficult! Because the iPhone NAND is not a single change, and the cost of CPU is also expensive, the success possibility is not big, you will only only waste money but also time, so it's best to give up in this situation.

4. Booting with white apple screen, reboot after blue screen , many lines of English, red screen or reboot after constantly changing the iPhone 5s screen color.

If you turn on with the white apple screen, you need to find out that it doesn't boot or the display is abnormal. You can connect Ace assistant after boot. If you can boot normally, you can connect online, and Ace assistant can read the information of the cell phone, which means that the phone can boot normally. If Ace assistant prompts "point trust", it also means that it can boot normally. So the problem is shown in the display part, the solution is to restall or replace the iPhone 5s touch IC.

5.U2 damage will cause the boot failure, white apple screen, boot current value stays at 200MA, In most of case, U2 chip damage will cause white apple screen or current value stays at 200MA.

6. The iPhone 5s stays in recovery mode when customer sends to repair. Recover the device to see if there are any error code, if it reports error 4013, then you need to replace a compass IC or U2, if not working, replace a new NAND. if it reports error 9 or 14, it means U6 or NAND is damaged, firstly replace U6 chip then try to replace NAND.

7. if the boot current value is around 50 Ma,  connecting computer will automatically enter the DFU mode, which is mostly CPU does not work, in this kind of case, you can check whether the resistance surrounding the CPU is false welded or dropped.

More cell phone repair skills you want to know, just check on www.vipfixphone.com

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...

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...

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...