The iPhone 6 plus got touch failure or jump randomly before dropping, it can return to normal after press switch. When repair touch IC, the iPhone 6 Plus fell to the ground, the bottom right corner of the touch screen glass is broken, and the front camera turned black, but the iPhone still can be used. A few days ago, when turn it on; the screen is blurry when the white Apple LOGO appears and it can't enter the IOS. Now, it can't boot, and the current is 150mA. GPS antenna was broken and now it shows GPS signal is weak when moving.
Remove the motherboard (picture 7-3-1), it is shocking to us. The touch IC and WiFi chip have been repaired, it doesn't matter, and we can fix it by replace the new chip. The most important problem is the capacitance resistor and inductor of back socket was empty solder. As shown in picture 7-3-2.
A row of resistors and capacitance, also have bad chips, it's really a headache. Connect motherboard to DC power supply, the current jumps between 70mA and 120mA. The failure is as follows:
1. The CPU was missing solder
2. Touch jump wire
3. Camera
4. Other problems caused by CP
First repair CPU, omit the process, the result is shown in the picture 7-3-3.
After repair CPU, power on iPhone and test it, there still have many diode data of socket are abnormal, put it under the microscope, and we directly remove it and re-fill it, as shown in picture 7-3-4. When we remove it, we can find that the glue is gone, but the glue on normal motherboard small components won't drop.
After dealing with these, test it again, still no display. Now, we can only do it step by step. Measuring display power supply, all is normal. Measure the resistance of the display socket, we found there is no 5.7V power supply, but when measuring the voltage behind it, it is present, so we suspect that it is disconnect. After measurement, it's really disconnected. Solder jump wire as show in picture 7-3-5 and 7-3-6.
After jump wire, test it, the display back to normal, but the touch function doesn't work. Solder jump wire with soldering station to fix touch MI pin, as show in picture 7-3-7.
After soldering the jump wire and chip, enter the IOS and test it, there still have a problem with the front camera, and there is a vertical bar where the rear camera takes pictures. The problem of rear camera is caused by camera 2.5V power supply direct connect and PVCCMAN short connect. As shown in picture 7-3-8.
The problem with the front camera is that the inductor is connected directly to the lead, as shown in picture 7-3-9.
Fill the missing components and measure the resistance data, we found that the value of the front complement element has 10 Ohms difference. Power on and test it, both of the rear and front camera are normal. But the deviation of the front camera resistance may cause by CPU, now is good, maybe it will be damaged after a period of use. Picture 7-3-10
Finally, the problem of the iPhone 6 Plus has been solved, as shown in picture 7-3-11.
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...
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...
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...
A row of resistors and capacitance, also have bad chips, it's really a headache. Connect motherboard to DC power supply, the current jumps between 70mA and 120mA. The failure is as follows:
1. The CPU was missing solder
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