跳至主要内容

Solution: Why iPhone 6S Repeats Booting

When the customer came to send the iPhone 6S device, he said: "the phone keeps rebooting repeatedly, it was repaired before, but still have not been repaired well by two mobile phone repair shops."


After getting the phone, we carefully watched the mobile phone mainboard repair situation, and found that the barometer of the mobile phone was soldered with 4 or 5 jumper wires, but we have no idea what was the fault was fixed at that time.

Observe the iPhone 6s motherboard with a professional TrinocularStereo Microscope , it is found that there is a small dot near the barometer disappeared. Checking the WUXINJI
 iPhone schematicdiagram and bitmap, we get to know it is a zero ohm resistor.
 




After the short connection and installation, the iPhone 6s is tested OK. In order to ensure that the customer will not get any problems when he receives the handset, it will not be a problem if he wait for a night, until the second day morning, we found sometimes it still reboot repeatedly.

Is there a small hole in the barometer that causes a partial damage to the barometer? A barometer is directly found on the dismounted iPhone 6s motherboard, apply high temperature glue on the small hole and blown down the barometer with hotair gun. After the barometer replacement, the iPhone has no reboot failure after waiting for 2 days.


Conclusion: it's very important to observe carefully before cell phone repairs. Do not blindly fix the motherboard of a mobile phone. Now there are many control interfaces of mobile phone CPU, and it will cause very weird fault symptom when there is something wrong with it.

More cell phone repair solution please read at www.vipfixphone.com

评论

此博客中的热门博文

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...

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: Why iPhone X Voltage Keeps Jumping

After getting the iPhone X motherboard to test, we observe the current value repeatedly jumps between 0mA and 50mA on DC power supply , and it is different from the normal booting current. Next, test whether the power supply of every circuit is normal. PP_VDD_MAIN is measured 4.2V; PP_VDD_BOOST measured is 4.2V. PP1V8-ALWAYS is 1.8V, all the values are normal. But when testing PP1V1_S2, PP0V8_SOC_FIXED_S1, PP1V8_S2 and other circuit voltage that output by power chip U2700 voltage are jumping constantly. According to previous experience, voltage jump is usually caused by a power supply circuit of U2700 output. Measured with digital multimeter , there is no short circuit was found for the dipole value of all power supply to ground. We repaired iPhone 7P before and know that if crystal oscillator is false welding can also cause voltage jumping, And if iPhone CPU  power supply is abnormal also can cause voltage jumping. Check the crystal oscillator we find no problem, then check th...