How to repair a volume button fault effectively?

Once one of phone part was used frequently, maybe it will cause a fault, So can i ask a question which part was used mostly in most smartphone?

Like the topic said, the volume button, when you listen music, making call with your family or watching some video, you will use it. So there exist a great possibility to happen fault on this button.

Today, what we will repair is the phone volume video fault, the up button has no reply while the down button runs normally, so maybe one of them happens IC control fault, anyway, we need to confirm it.

Firstly, we need to check the  iPhone volume button, we found the volume down button runs normally while the up button has no response, so we have to contrast diode data to check it.

The J4701 socket fourth pin is volume up button, measure its diode data with Fluke 15B+ Digital Multimeter, the data is normal, check its voltage, it only has 0.3V, while the normal voltage should be 1.8V. The voltage was pulled down, considering whether is caused by load leakage on the path.

Check iPhone schematic diagram on WUXINJI Dongle, we know that the load on this circuit has capacitor C4713 and diode DZ4713. If these two components leaks, it will cause this circuit voltage is pulled down. Remove these two components, and the voltage measured still is 0.3V.

According to the iPhone schematic diagram, we know that this circuit doesn't have a pull resistor, which means that the pull voltage is done through the internal CPU. Measure the diode data again, the data is normal, which means the iPhone CPU doesn't have a virtual weld, it is caused by local damage.

Use the method that borrow the voltage from other circuit, modify a 1.8V pull voltage on the volume button. Based on bitmap to find the most recent circuit can be used to borrow voltage, the picture of the modified circuit is as follows:

Borrow a 1.8V voltage from compass power supply, and connect a 1KΩ  resistor on capacitor C3000 1.8V end to capacitor C4713 non-earthing end. And then measure the fourth pin on J4701, it has 1.79V voltage.

Assemble the volume button, then check it, we can turn the music sound freely, it shows the repair result was succeed.

Checking and Fixing iPhone 6 iTunes Error 56

As we known, each fault has an official name, same with the camera fault, error 56.

After we got the iPhone 6, we do thought it just happened Wi-Fi connect fault, but when we flash it, the error code 56 occurred on the screen, so  we need to disassemble it and check the IC parts. Let us start.

We can ignore the issue of iPhone baseband CPU, if iTunes reports unknown error -1, and then we need to repair iPhone baseband CPU part. But this iPhone can be used normally before flashing, so we suspect the NFC module is damaged; now we decided to remove the U5301_RF first.

Remove U5301_RF by QUICK 861DW hot air rework station, and the measure the diode data for bottom pin circuit by multi-meter, after measurement, we found it is short circuit.

Open the WUIXNJI Dongle to check iPhone schematic diagram, we know that this circuit is connect to NFC power supply, CPU, and two small capacitors.

Now, we first consider NFC power supply, put it under the 7-45X Trinocular Stereo Microscope, and use hot air gun, and use tweezers to remove it quickly, next to it are two iPhone touch ICs.

After remove it, we measure it again, now the circuit is normal, and then replace the new IC to it.

Now, assemble the iPhone, and flash it again, the iPhone flash completed successfully.

4 Case Summarize for Audio Fault Repair

As a professional repair man, we received the repaired phone constantly, each iPhone has different fault, like Phone motherboard fault, water damaged, NAND fault or screen broken and so on...

We usually will choose a high efficient way to deal with different fault. But it needs yours enough patient, it won't be a loss for each other if it caused the secondary damage.

About the audio fault expresses frequently in recent, so we decide to share an article about this fault, it will help you save money instead sent your phone to the repair shop. Following the repair way:

1. No voice when calling

When you are talking to someone on your iPhone 7 or iPhone 7 Plus, you don't hear any voice. In this case, first you need to test the iPhone recording function to check whether it works normally.

If the recording function is normal, but the call is abnormal, then the problem is basically in the iPhone baseband part. In order to repair it, put your iPhone on the WL Aluminum Alloy Pad, and then you need to disassemble the iPhone by phone opening tools, remove the iPhone motherboard. Take off the iPhone baseband CPU, and then re-install it.

If the recording function is abnormal, then the problem is basically in the audio decoding part. In order to repair it, you can re-install audio decoding or replace the new one.

2. The other party could not hear my voice during the call

When you receive or make the phone calls on your iPhone 7 or iPhone 7 Plus, you can hear the voice from the other person, but the other person can't hear your voice, whether in normal call mode or hands-free call mode, the problem is the same.

In this case, you need to replace the iPhone Tail plug Flex Cable, reinstall or replace the iPhone audio decoding.

3. No voice when recording

When you use iPhone recording function, there is no voice, and then you need to replace the iPhone Switch Power Flex Cable.

4. No voice on receiver

If there is no voice when you use receiver, then you can replace the new receiver or receiver flex cable, re-install or welding audio decoding by QUICK 861DW hot air rework station.

It confirms what we have said, not all of the same fault was caused by the same fault sources. It needs your checking patiently. Hope what we shared can be useful for your understanding about phone repair.

Analysis iPhone 6S audio and vibration fault step by step

Not each of iPhone same fault was caused by the same reason.

There still exist uncertain reason for phone fault, today we will share an article about iPhone 6S audio and vibration fault. Maybe you doubt the IC fault,  just following the below article:

We connected it with the DC power supply, test the audio IC one by one, we found some unusual,the receiver signal CODEC_TO_RCVR_N CODEC_TO_RCVR_P of the normal call mode comes out from the iPhone 6s audio IC, passes the FL3153 FL3154 to the receiver flex cable interface J3100, and then sends signal to the receiver to make a sound. There are two microphones in the normal call mode, one is LOWER MICI, the other one is LOWER MIC4. And there are two microphone signals, one is LOWERMICI_TO_CODEC_A1N1_P LOWERMICI_TO_CODEC_A1N1_N, and the other is LOWERMIC4_TO_CODEC_A1N2_P LOWERMIC4_TO_CODEC_A1N2_N.

After we compared it with the diagram shows, we know that the two sets of microphone signals pass the charger port flex cable, charger port flex cable interface J4600, and then respectively through inductance FL4610 FL4611 and FL3613 FL4614 to Audio IC--U3500. The microscope power sent by audio respectively pass inductance FL4612 FL4615 and then through the charger port flex cable to supply the two microphones.

Then we decided to enter the HF mode, to check the loudspeaker signal, it can directly see the speaker code.

SPEAKER_TO_SPEAKERAMP_VSENSE_P, SPEAKER_TO_SPEAKERAMP_VSENSE_N comes from ringtone amplifier IC--U3700, and passes the FL4630 FL4631, charger port felx cable to loudspeaker to make sound.

The hands-free microphone signal (the hands-free model microphone is on top of receiver flex cable) passes through the receiver flex cable interface J3100, passes through the inductor FL3155 FL3156 to the audio U3500, and the audio U3500 sent the audio U3500, the HF microphone power PP_CODEC_TO_FRONTMIC3_BIAS through the inductance FL3150 to the receiver's flex cable interface J3100, and then supplies to microphone through headphone flex cable.

As of the iPhone 6S was designed  a videotape microscope which is on top of the power, it also can cause the video or hear only murmur, so we need to enter the HF mode to check it.

The ringtone amplifier IC--U3700 damage. Besides the ringtone, it will cause no hearing, no vibration. The vibrator is controlled by U3700 and U3800. If there is no vibration failure, besides vibration and charger port flex cable, most of them are damaged by U3700 or U3800. Use PPD 861D+ Hot Air Station to remove the damaged part and replace new one will solve the problem.

Then we have checked it for many times, after we assemble it, if there is still no sound completely, just need to the audio U3500. But just part of the sound, check if the related inductance are dropped out, short connect by jumper wire, then directly replace it, it also can be solved.

Two different way for solve iPhone water damaged

Water damaged will cause different fault, so today we will share two case which will match two different deal ways.

But the first step, we still need to disassemble it while opening the wuxinji diagram to ready for the next repair.

Case 1

When supply power to measure the iPhone motherboard, there is large current alerts on DC power supply display screen, which means that there is a leakage phenomenon. Generally, when powering the motherboard and then it shows power leakage issue, the Rosin method is the best choice.

Use Fluke 15B+ Digital Multimeter to measure the diode data for iPhone battery interface positive, the data is normal. Continue to measure the diode data for main power supply VCC_MAIN circuit, finding that the diode data for this circuit line is too small, which means that there is a short circuit here.

Smoke the iPhone motherboard to white with rosin, add voltage on VCC_MAIN, after for a while, we found a capacitor is shorted.

With the help of QUICK 861DW rework station and tweezers, we remove it smoothly and quickly. After remove that capacitor, measure it again, the data is normal now.

Install the iPhone to test, the iPhone 6 can be turned on smoothly.

Case 2

When the iPhone motherboard is being measured by powering, it won't leak, but when we press the iPhone power button, the current stuck on 200mA. Obviously, a load on the iPhone power IC is short-circuited.

Use multimeter to measure the resistance of each output grounded on the iPhone power IC, when the PP1V8_SDRAM circuit is measured, we found the problem, the PP1V8_SDRAM circuit is shorted, because the data for C1243 is too small.

Put iPhone motherboard under the Phone Repair 7-45X Trinocular Stereo Microscope, and then apply some rosin on motherboard, and then use Quick 861DW hot air rework station to smoke it, till the motherboard turns white.  Increase the voltage in the C1243, after a while, we found a capacitor is shorted.

Remove this capacitor as usual, and then measure it again, now the data is normal.

Assemble the iPhone to test; now the iPhone 6 can be turned on smoothly. After get into IOS, test all function on iPhone, everything works well.

Hope the above two solution can be useful for your fixing.

Handle iPhone 6S Plus compass fault Step by Step

We will share a new repairing way for the new fault.

iPhone 6S Plus happens the compass and screen flip fault, maybe its master don't use it carefully. And according to our ever experience, maybe some chips was damaged as of the abnormal using.

Firstly, we need to find the fault part, so have to disassemble it with the pry opening tool, then we start our fix process.

If the iPhone 6s Plus screen flip is abnormal, it will affect the function of compass, so let us start our fix process.

1. Use opening toolkit to disassemble the iPhone 6S Plus, we have to replace a new gyroscope chip with QUICK 861DW hot air station at suitable temperature, you will also need to carefully take off it with a precision tweezers. However, it doesn't seem to be a problem of the gyroscope chip since the same problem still exists after that.

2. Take off the iPhone 6S Plus motherboard, then observe it under Trinocular Stereo Microscope microscope, it is found that there is corrosion trace around the iPhone 6s Plus compass chip. When we remove the compass, we find a spot is oxidized. As shown in picture 15-10-2.

3. Apply some Mechanic BGA solder paste on pad and then weld the original compass chip back, it still doesn't work.

4. Replace a new compass chip on the motherboard, finally the iPhone 6s Plus flip screen and compass function restores normal. (we estimate the compass chip is damaged by liquid, thus the screen flip function is also not normal).

5. Re-stall the iPhone to test , all the function is normal now!

How to fix iPhone 6P boot fault ?

Most of fault needs to disassemble, the next one can't be avoided.

The customer sent the iPhone 6P to us which along with the boot failure. Before we check it, we need to know the normal value, the data can show everything.

Disassemble the iPhone 6 motherboard and connect DC power supply while open the wuxinji diagram on the computer, there is no short circuit, then triggers we find that the current directly jump from 400mA to 1A, the main board is short circuited, now taking off the main board to observe, the iPhone 6 Nand was repaired before.

Use Fluke 15B+ Digital Multimeter to measure the power supply around NAND, it shows 1.8V short circuit, we are going to remove the NAND to observe under Trinocular Stereo Microscope. As shown in picture 15-8-1.

picture 15-8-1.

It's a little dirty on Nand chip parts. First, we reprocess the pad. There were 2 points were dropped, as shown in picture 15-8-2.

picture 15-8-2.

Measure the two points and see if there is any problem. The point is measured as ground connection (the normal point value should be infinite).

Disconnect the jumper wire soldered by the last repairman.

After processing, measure the iPhone 6 NAND CHIP, we find it's normal power supply 1.8V. Without NAND installation, we connect DC power supply to see the triggered current is 70mA, it's DFU mode when connect with computer(it happens when no NAND on motherboard or NAND doesn't match with CPU), then we remove the NAND on WL PCIE Test Fixture to see if it can be read, the result shows the NAND chip is not bad, now we re-install the NAND.

The triggered current is still 70mA, so we suspect that the NAND chip is not original, install the motherboard back and connect a computer with recovery mode, we want to check whether it can read the serial number of NAND. It can be read, so we continue to recover the data til succeed.

Unfortunately, we need to the ID identified  during the next repair process, if we unlock it, it may cause the data damage. So we have to request to our customer, we need to assemble it now. Later  we will continue this fault, thank you for your reading.

Fast Fix iPhone 6 No Display

The customer sent the iPhone 6 to us without any words, so we have to test it step by step. right, he said it is black screen when he playing the game. So we doubt there exist some fault in capacitor.

Fist, open the wuxinji diagram and find the iPhone 6 display socket circuit diagram.

Next, use Fluke 15B+ Digital Multimeter to measure the diode data of iPhone display touch socket, finding the 26 pin circuit is shorted; The display screen is positive 5.7V.

According to iPhone schematic diagram, we know that this circuit is output by iPhone display touch IC, there are 6 filter capacitors on this circuit line. 

Based on previous repair experience, we judged that the filter capacitors are damaged. Put iPhone motherboard under the Phone Repair 7-45X Trinocular Stereo Microscope, and then remove the filter capacitors one by one, when breaking into the third filter capacitor, the data measured is normal.

After you finished the above step, install the iPhone, boot it, we can see the logo appears on the screen. Then we test other function, all of it is normal, so the repair ends here.

Solve iPhone 7P Charging and Sound Fault

If you are not a professional repair man, we advise you had better not do the repair work by yourself.

Today the repaired iPhone really is an accident which can be avoided, the customer said he want to try to repair it by himself, he disassemble it with his own tool. Obviously, the result is not good, maybe there happens some fault during he dealt.

The directly words is that you need to spend a high cost than before the little fault. If you sent it to us from the beginning, or another said, you can purchase some phone repair tool to support your work. You know the charge fault always along with the motherboard, we have to disassemble it and check it from inside to outside. Okay, let us start our today's fix work.

Firstly we need to boot it without battery with the charging cable, but it still no any charge status. Connecting it to computer, we found the computer can't recognize the iPhone, based on our ever repair experience, we can basically confirm that the fault was caused by iPhone USB control IC.

Disassemble the iPhone USB control IC from iPhone motherboard, and then measure the diode data of iPhone solder joints on solder pad with Fluke 15B+ Digital Multimeter, finding that the diode data of iPhone USB IC C3 pin is infinitely large. This signal point is connected to iPhone main audio IC by through resistor R3104.

There are three reasons can cause this case, one is resistor R3104 is damaged; the second one is the iPhone motherboard dropped pins and disconnection; the third one is iPhone big audio IC is damaged. 
Picture 15-2-1

Remove the iPhone main audio IC and check it under the 7-45X Trinocular Stereo Zoom Microscope, there's a pins dropped and disconnect. Fix the jump wire of the pin, and replace the iPhone big audio IC. Now measure the diode data of USB IC C3 pin again, the data is 480, and it’s normal data.

So we need to re-install it and insert the charger again, test it again ,we get the current value is 1.13A, according to the wuxinji diagram shows,we can know the charge function is recover normal.

For the sound fault, during we testing, we found there exist some dropping pin, so we decide to change an new iPhone audio IC.

So like what we have talked, from the beginning, it is just a little fault, but if you don't deal it carefully, maybe it will cause a big problem. Though we have repaired, it is under the professional tools situation, it will need a high cost for this repair. 

But the result is goods, the phone can be used again and all of the function shows normally. Hope what we shared can help you avoid this fault.