Repair iPhone 6S stuck on white apple logo

After receiving the iPhone 6S, we got through a call with our customer, then we know what happens.

We reboot it, enter the DFU mode which can be online, so we ensure it has nothing to do with U2 fault

While there is automatic black screen after the white apple appears. The computer prompt can not jump from DFU to recovery mode. This is often caused by iPhone NAND or CPU.

The power supply of the iPhone 6s can be measured according to the WUXINJI schematic diagram. The two 1.8V are on C1534 and C1560 respectively, 0.9V is on C1548, and 3.0V is on C1502, and the NAND voltage is normal. You need to take down the pin resistance of the NAND to see if there is a break between the CPU and the NAND chip.

At the same time, you need to test whether the NAND itself is damaged. The protective measures should be pre heated to remove glue, and the temperature is about 220 degrees. Choose the thinnest blade, except for the right side of the adhesive, there must be some small resistance around it. If it falls, it must be filled.

The QUICK 861DW hot air gun can be selected to remove the NAND chip, and the heat transfer area is large, the temperature should be set about 350 degrees. When heated to a certain extent, you can tentatively take the thin slices and insert them into the hard disk. When the tin starts melting, you can pick them up. Do not use great force to avoid dropping the NAND and pads. (temperature is related to equipment and personal techniques).

        

  

After testing, the NAND pin is normal, take the WL PCIE programmer(VC748) to read the data.

   

NAND data is displayed normal, remove broken line and NAND problem, reinstall the NAND to reflash the iPhone, all the function is normal now!

How to fix iPhone 8 no service

Have to say it is the first time i receive iPhone 8 from my customer,  it is the latest iPhone model.

My friend told me there happens no service after inserting , so we doubt there happens some fault inside of it, we need to check the current and value.

For a dropped iPhone, mostly the iPhone solder pad pins are missing, or the iPhone is short-circuited by dropping. The iPhone 8 plus was dropped before, so we suspect that the solder pads are off the pins.

After disassemble the iPhone, we found the iPhone has been repaired by other repair man, the DSM_LB_E and DSM_HB_E chips on the iPhone motherboard had been removed.

Use Fluke 15B+ Digital Multimeter to measure the diode data for iPhone solder pad, we found the SCLK_HB_LB_DSM_FILT_E signal for the DSM_LB_E and DSM_HB_E IC is short-circuited.

Open the WUXINJI Dongle to check iPhone schematic diagram and bitmap, we found the previous repair man installed the R1608_E resistor in the C1602_E capacitor position, the position of the C1602_E capacitance on the schematic diagram is not installed.

Picture 18-4-1

Use tweezers to remove the resistance on the C1602_E capacitor position, and then use QUICK 861DW to solder it to the original place, solder the jumper wire to the missing pins on the solder pad, and welded the component chips. Now install the iPhone and test it, but the problem still there.

Disassemble the iPhone, observe the iPhone motherboard under the 3D Digital Microscope, comparing with the iPhone schematic diagram, we found the FL1501_E inductance missing, but it's installed on the schematics diagram.

Picture 14-4-2

Connect the missing inductor directly，and then turn on the iPhone to test.

Picture 14-4-3

Now the signal is normal after insert the SIM card, and the phone call is normal, the repairs end.

This failure is caused by missing pins on solder pad and dropped components

Solutions for iPhone 7 Wi-Fi Faults

What the topic we will talk is related with phone NAND, while Wi-Fi MAC address usually along with it, so we may need to check it carefully.

First step, replace it with a new one, then get the new Wi-Fi address, check the NAND Wi-Fi parts, let us start.

Then the next step is to remove the iPhone 7 NAND chip. As shown in picture 1.

After that, put the NAND chip on WL PCIE programmer to unbound WiFi. As shown in picture 2.

WiFi unbound is successful after installing to test, but the WiFi can not be turned on. Where is the problem? It's the same situation after reflashing the iPhone.

In the past, 6S WiFi unbound was sometimes unsuccessful, so we remove it and unbound again, it is OK this time .

WiFi is normal. But no vibration can be found in the installation, the vibration chip can be replaced or redo with iPhone 7 BGA reballing stencil.

Wi-Fi faults usually along with the NAND, so it is not easy for common phone repair shop, but it can be used to do a totally examining for your device. Maybe you can try the tools we used in this article.

Pay More Attention On iPhone 6 Map Navigation Diagnostic

iPhone 6 map navigation is not a common fault, which means we also need to check it carefully.

Honestly, not all of our phone faults are familiar with us, we still need to pay enough attention on it.

While according to the attached file, we know the iPhone can be positioned, but the location coordinates don't move when the navigation route, this failure may be caused by signal instability, or the GPS signal channel problems.

First test the iPhone 6, open the Maps App, the location coordinates is not updated when navigating, and it always in the same place.

Disassemble the iPhone by phone opening tools, remove the iPhone motherboard. Open the WUXINJI Dongle to check iPhone schematic diagram, the GPS signal through some switches to the U_WTR_RF RF IC and then to the iPhone baseband CPU, as shown in

Some small switches are covered by black glue, so we're not consider this factor first. Because it was first passed through the U_WTR_RF RF IC and then to the iPhone baseband CPU，so we can replace a new U_WTR_RF RF IC.

After replacement, install the iPhone to test, the navigation route update location can move normally, the repairs end!

This failure is caused by the damaged U_WTR_RF RF IC.

Then it means we got the result we want, next we will use the professional tools to disassemble it and repair it.

How to check iPhone 5SE home button fault

According to the past experience, we do have some summarize for it.  iPhone 5SE fingerprint faults is not a specific problem, but for now, it may be a little strange.

Anyway, there forever likes its beautiful size, we don't refuse it, let us start today's fix process.

1. The iPhone SE fingerprint can't be opened smoothly

Disassemble the iPhone SE by phone opening tools, and then remove the iPhone SE logic board.

Use multimeter to measure the iPhone SE to check whether there are the 1.9V (PP1V9_MESA) and 3.1V (PP3V1_MESA), you can test it by pressing the iPhone power button.

If the 1.9V (PP1V9_MESA) and 3.1V (PP3V1_MESA) doesn't exist, then you can fix it by short connect FL4100 and FL4105.

If both the 1.9V and 3.1V are exist, then use Fluke 15B+ Digital Multi-meter to measure the diode data, if the data is infinitely large, check the corresponding circuit, and short connect FL4110, R4111, FL4112, FL4114 and R4116.

If the voltage or diode data is abnormal at the beginning, after repairing, the data back to normal, but the iPhone fingerprint still can't be opened, you can fix it by flashing iPhone or erase all data on iPhone SE.

2. If the iPhone SE fingerprint can be opened smoothly, but the iPhone home button is not responding when adding a new fingerprint.

Measure the diode data for this pin  to check if it has the diode data.

If it has no diode data, then use QUICK 861DW to short connect FL1407.

If it has the diode data, then use Precision Titanium Alloy Tweezers to replace the new U4040, because the damaged fingerprint power supply U4040 can cause iPhone SE adding fingerprint failed.

After you finished the aboved operation, check it again. If it still can't work,  we may advise you our latest phone fingerprint repair tool, it will be a useful way for home button faults.

Repair iPhone 5 Charging Fault Carefully

But if it happens some fault, what should you do? especially when you have used it so many years...

Honestly, i don't want give up, so i am glad to repair it and make him alive again

The charging part of iPhone 5 is made up of Q2, U2 and U7. As shown in picture 1, the circuit diagram of the charging port J7 can be inquired on the WUXINJI dongle.

The 5V voltage sent from the tail plug passes through the Q2 to send two 5V power supply. PP5V0_USB_PROTECT and PP5V0_USB_RPROT were sent to U7 and U2 respectively.

In addition, there are two detection pin in the middle of the battery contact J6! they pass through FL10, FL11 respectively and send to power IC-U7, FL10, FL11, in actual cell phone repair, it is found that the 2 pins are very easy to fall off, causing the cell phone can not be charged! and keep reboot again and again!

If there is a problem of charging, plug in the data cable, use Fluke digital multimeter

to measure whether C304 has 5V output, and measure whether C272 has 5V output.

If not, you need to test the iPhone 5 charging port flex cable, short connect the Q2.

If both of them can be measured 5V, then the problem is in U2 or U7.

In addition, the battery detection pin problem will cause abnormal charging, the more charging, the less battery power will be, and also there will be automatic restart fault.

So maybe there exist a deeper question, we need to disassemble it and use the more professional battery diagnostic tool, later we will update.

Detail Analysis for iPhone 5S Charging Fault

Fault description: iPhone 5S happens charging fault and power drains fast

According to our ever repair experience, we need to check the inside and find the sources faults ,it it is necessary, we may need to replace it with a new one.

Check iPhone 5S circuit diagram on WUXINJI Dongle, we know that after plug the iPhone lightning cable, the charge voltage PP5V0_USB_PROT first passes through Q2, then to U2, and then to the iPhone power supply IC--U7, we can measure the voltage of 5V to U2 by Fluke 15B+ Digital Multimeter at point C272, and the 5V voltage can be measured at point C304.

If 5V can't be measured at C304 and C372 points, which means that Q2 is damaged. In this case, we need to short connect Q2，as shown in the following picture 1-1

If one has 5V and the other not, which means there is a disconnection. In this case, we will use QUICK 861DW hot air rework station to solder a jump wire from C304 to C272.

Note:

1. If the C304 or C272 doesn't have the voltage, it will cause iPhone can be charge only when it is turned off or is the hint that the accessory is not supported

2. The iPhone 5S USB control IC--U2 is easy to damage, and then cause iPhone cannot be charged, cannot connect to computer and won't boot issues, so we need to replace the iPhone USB charge IC--U2.

3. The damaged iPhone battery and iPhone tail plug flex cable also can cause iPhone charge failures, such as won't charge,  "this accessory is not supported", or the percentage of charge icon is getting less when the iPhone in charging, so we need to replace the new iPhone batter or iPhone tail plug flex cable.

Then, check it again, charging and restarting it, check the charging process.