How to fix iPhone X rear camera problems

Fault Description:  iPhone X rear camera happens problem after disassembling it.

We got the attached file which described the iPhone rear back camera connector socket happen abnormal. While we have to observe the board carefully under stereo zoom microscope, we notice the board is a little deformed. Seeing the pad, it's a very tricky problem, but we still need to solve the fault.

First, it is urgent for us to process the J3900 rear camera soldering pad, flatten and plaint tin again, next, soldering a jump wire.

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After finished welding jump wire, we need to wrap it around one by one, and apply the UV flux oil. One important is that we also need to measure the resistance value by digital multimeter, luckily, it is normal, now we can weld the soldering pad.

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Then solder the ball on the jump wire, welding the base. Welding tin to the untouched pin and soldered well. Next, assemble the iPhone X and test, to my surprise, the function of rear camera have recovered normal. The procession of fixing iPhone X rear camera connector socket.
come to end.

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How to fix iPhone 6P infinitely reboot after white Apple appears

Fault Description: iPhone 6 Plus reboots infinitely after the while Apple logo appears.

According to our ever experience, the NAND, the Logic EEprom IC may cause this issue, so we need to check the phone motherboard, absolutely we need to disassemble the iPhone 6 Plus.

Measuring the grounding resistance value and power supply for the iPhone CPU, both measured value are normal. Next measuring the working condition of the iPhone Nand flash, it's also normal. When measured the iPhone eeprom IC, we found the bus (AP_TO_EEPROM_I2C) connected to the iPhone logic eeprom IC and the iPhone CPU（VC542） has some problem, the grounding resistance value for one of clock bus is more than 600, but the normal data should be around 400, seems there is a disconnection or the pin of the iPhone CPU is empty-welded.

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Because there are only 1 bus has the problem, so we choose to dig the iPhone CPU, so that we can solder the jumper wire. According to check the iPhone schematic diagram via ZXW Dongle, so we can confirm the areas of excavation. Put iPhone motherboard under the Stereo Zoom Microscope, install the new blade to the handle, and then we can start to dig the iPhone CPU.

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Dig through the iPhone CPU upper layer , then start to dig the iPhone CPU lower layer, now is the most critical position，we need to be very careful.

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Dig off the first layer of ground circuit wire and leak out the circuit wire of the second layer of signal.

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Carefully dig out the circuit wire, apply the green UV oil on the extra area, and connect another side to the AP_TO_EEPROM_I2C_SCL pull-up resistor.

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Use digital multimeter to measure it again, the grounding resistance value is back to normal. The iPhone 6 Plus can enter the IOS system after booting, the display is normal, which means the failure has been fixed, the repairs are end!

How to fix iPhone 6 no touch fault after dropped

Fault Description:  iPhone 6P can't be turned on after being dropped.

According to the attached file, we found there happens a ineffective touch, we use a replaced screen to test it, but still no works, so we may need to disassemble it.

The bottom of the UMT board is easy to be disconnected, so we plan to dealt with the no- touch fault at first. There are two ways to take the IC: one is to take out with tweezer; the other is to pick up from the side of IC. After removed the iPhone touch IC, reinstalled the machine, and the phone boot White Apple restart, turn on start current run at 300mA.

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We haven't repair other place else, only remove the touch IC and check the resistance of the bottom of the board. The resistance is normal after tested by digital multimeter, such problem we haven't meet before. I am a little anxiety see the fallen UMT. Since the start current is too large, take U2 down and look at the starting current, he result is the same without any change. Measure the resistance value of U2 pin habitually.

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We found that the PP3.0V on F4 pin is short-circuit, and this line has a large power supply, fingerprint power supply and U5411_RF of the head.

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Power-up again, we found U5411 - RF heating, disassemble the two components connected with U2, then turn on, we can determine the damage is caused by U5411. Turn on, the iPhone jump from 300mA and White Apple does not enter the system, after replaced U5411, the problem was being resolved. Install the touch IC and test function, occurs a new fault. There is no service after turned on, and no serial number. For this fallen UMT motherboard baseband failure, we remove the baseband CPU directly with QUICK 861DW Rework Station, then the fault will be resolved through welding wire on the left upper left V1, U1.

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Finished solder a wire well, then apply UV fluxes oil, re-plant tin on baseband CPU, and installed , finally, test function, all is normal. Repair work finished successfully.

Solve iPhone 7 no service after memory expanding

Fault Description: iPhone 7 happens no service after been expanded to 128.

The first step we do is to brush it into the latest iOS system, we found it can enter the system but no service.

So we need to disassemble the iPhone 7 to check the iPhone motherboard, with the digital multimeter to test the current and voltage,  to measure the power supply capacitors around the iPhone baseband power IC, we found the PP_1V0_SMPS5 is shorted. Generally, this case is caused by a short circuit of the iPhone baseband. Remove the iPhone baseband power, and then measure the PP_1VO_SMPS5 again, it's still shorted.

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This is a designed flaw of iPhone 7 Qualcomm version, the iPhone baseband S5 power grounding connect point seems to be disconnected, but not, and it cause iPhone baseband burned.

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The solution is put iPhone motherboard under the Trinocular Integrated Microscope, re-connect the S5 grounding connect point, and re-install the iPhone baseband power, borrow a PP1V8_SDRAM on the C3211, pass through a 2.2K resistor to C5701_RF, and then forcibly pull up PP_1V0_SMPS5.

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Finally, install the iPhone 7 and test it, now the iPhone signal is normal, the iPhone is working properly.

Solutions for iPhone 6S turn on failure after replacing the card slot

Fault Description:  iPhone 6S happens slot shrapnel is broken and can't read SIM, the peers blew it blind.

While after we checked, we found the card slot is not repair well so that the machine can't be turned on.

The customer said to me that the phone can be turned on but have no display, I feel that this is not the real fault. When power-up, test with digital multi-meter, the current is 100 and have no change, and we start to repair after communicating with the customer.

The iPhone can be online, DFU mode, which should be due to blowing the card slot too over resulted in iPhone NAND flash pseudo-soldering, and there is no brush machine at start.

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Disassembling the NAND flash with QUICK 861DW Hot Rework Station, we found a useful electric A5 pin, the point on the NAND flash is big, it will be fine by flying a line from the side capacitor to fill the curing.

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The NAND flash tested no problem, reforest tin again, and test the resistance of the bottom board before installing the NAND flash. Install the NAND flash after confirm that there is no problem. Turn on the iPhone, the phone go into the system normally. Next, the we need deal with card slot, it is difficult to remove the card slot, but simple to install. The card slot removal can be opened with several fixed pin through the hot air gun, or the professional stainless steel scissors , clip the outer case gradually.

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Since the original card slot have damaged, we can remove it from the discarded board in high temperature. This will ensure the integrity of black glue inside the card slot. When install the slot card aligned pin pressed with the tweezers set. I use low temperature tin, so blow from the front won't affect the NAND flash on the back. After loading the card test, the card read, signal, and call function are normal.

Let us talk about iPhone 6 blurry screen

Got the iPhone 6, while the attached file described the screen is blurry after booting. While we have tried to replace it, but it still keeps the same, so we have to disassemble it to get the phone motherboard.

After removing the iPhone motherboard, we found the upper part is seriously deformed. For the iPhone blurry screen problem, first we need to measure the grounding resistance value of the iPhone display socket J2019 via digital multimeter, the resistance value all is normal. Since the resistance value is normal, next we need to remove the iPhone display IC U1501.

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Measuring the grounding resistance value of the iPhone display IC J219, we found the A4 pin is shorted, A4 pin touch 5.7V power supply, it is connected to iPhone black touch IC and some filter capacitors. Because the upper part of iPhone motherboard is deformed seriously, and the iPhone black touch IC is easy to damage, so remove the iPhone black touch IC.

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However, it is still short-circuited after remove the iPhone black touch IC, seems it's not the problem of the iPhone black touch IC. Next we need to use QUICK 861DW hot air rework station to remove the filter capacitors that connect to it, after remove the filter capacitor C1577, the resistance value is back to normal. Re-install the iPhone black touch IC and iPhone display IC.

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Connect iPhone display screen, and the measure the iPhone 6 with DC power supply, turn it on, the iPhone 6 displays normally. Entering the IOS system, the touch function tested is normal, the repairs end!

Solutions for iPhone 6 no speaker sound

Fault Description: iPhone 6 happens no speakers when answer the call, meanwhile there was no sound when playing music with speaker.

After received the phone, we turn on the power. Then go to Settings - Sounds - Ringtones. Select one from the list. The iPhone 6 has no speaker sound. Everything works fine when you plug in the headphones, which indicates the normal state of the iPhone audio IC. Therefore, the fault may be related to the speaker and audio power amplifier circuitry.

Disassemble the phone and measure the resistance values of 1# and 2# on the flexible cable connector of the charging port. The normal resistance value indicates a normal speaker buzzer.

Continue to measure the resistance between 1#J1817 and ground, 2# with digital multimeter, the value of current is normal, which indicates the circuit from the charging port connector to the U1601 is also normal.

Take out the logic board and check it carefully with LED desktop magnifying Glass, there is no phenomenon of water damage or mold.

Connect the DC power supply to the logic board, measure the power supply voltage of the U1601. The voltage is below 500 and the voltage is abnormal.

Connect the logic board PCB bracket. Use QUICK 861DW hot rework station to remove the U1601.

Test the resistance between A6# of U1601 and ground. the value is normal. Measure the resistance between A2# and ground, the measured value is "OL", A2# and B2# of U1601 are connected to the positive pole of the battery through L1604. So we judge L1604 is the fault part.

Replace the new L1604. Remove the L1604, we can see that one of the pins of L1604 has been oxidized and cannot be tinned. Apply some BGA solder paste to the pads, use heat gun to weld the new L1604. After that, measure the resistance between A2# and ground again, the resisstant value is normal.

Finally, we need to re-solder the chip U1601. Before soldering chip, clean the dirty on the separated U1601. Apply some BGA solder paste to the pads. Place the U1601 to the correct position and solder with heat gun.
Assemble the iPhone. Go to Settings > Sound > Ring. At this time the sound is output normally. The problem of iPhone 6 has no speaker sound have been cleared.