Short circuit error: iPhone 6 no display after dropping

It’s unfortunate that your iPhone fell, because most of the time, it means your iPhone is going to break down. In this case, the iPhone 6 fell to ground,  and then when we boot it, the screen shows nothing. This is so sad. But, don’t complain all we need to to is find the way to fix it.

First, disassemble the iPhone and energize the motherboard. The DC power supply displays 1.7V current that is short circuit and the adjustable power supply voltage is pulled down to 3.4V. The whole motherboard gets hot, especially the main power drive chip .

Second, deenergize it and measure the power supply of each circuit at motherboard through digital multimeter, find that the power supply of PP3V0_NAND of EEPROM is short circuit to ground and the resistance data is 0. The test points of PP3V0_NAND are shown in picture 1-1.

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Third, use solder iron to make rosin in the capacitance which connect PP3V0-NAND, then slowly turn the current button of adjustable DC power supply to increase the current limit, the inductor that is connected with PP3V0_NAND melts when the current is 3A. Therefore, this inductor is short circuit. Deenergize it and remove this inductor, as shown in picture 1-2.

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Fourth, after removing this inductor and plugging adjustable power supply, it is not short circuit. IPhone can get into IOS normally. Remove a inductor from the same place of the accessories pad to replace the old one. This problem was been solved.

Tips:

As this 3V voltage is parallelly connected many capacitors. It will take long to tear them one by one. Thus we use burn-in method to find the short circuit point. Put rosin on motherboard and set the adjustable power supply to 3V. Adjust the current limit to the lowest. Connect the negative pole of adjustable power supply to ground and connect the positive pole to the short circuit point. Then energize it. Slowly turn the current button of adjustable DC power supply to increase the current limit. The place that rosin melts fastest is faulty.

Solved: iPhone 6 was bent and then cannot found firmware version on it

There are a lot of case about iPhone 6 was been bent,  but that’s not the point of today. Today we are going to talk about the firmware of iPhone. The iPhone 6 cannot be found firmware on it after dropping. Because the rear cover was bent by dropping, but it still can work,  after we replace it, the firmware of “About iPhone” cannot be found.  It will take a lot of problems, we need to fix it.

  1.  Disassemble the iPhone 6, remove the motherboard. Observing from the side face, we can find that the board bends. We presume that the baseband or the baseband power supply is pseudo soldering. Energizing it and turn it on to test the power supply. VREG_SMPS2_1V25, VREG_SMPS3_0V95 and VREG_SMPS4_2V075 are normal. Only VREG_SMPS1_0V90 has no voltage. The ZXW DONGLE circuit diagram of these voltages is shown in picture 1-1.

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The test points of VREG_SMPS2_1V25, VREG_SMPS3_0V95 and VREG_SMPS4_2V075 in bitmap are shown in picture 1-2. They are all measured at the inductors around the baseband.

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  1.  According to experience, I cannot measure the baseband at CUP, which suggests that will cause no voltage on VREG_SMPS1_0V90. As the board bends slightly, we tear down the baseband and test it carefully, but I do not find any dropping pins. I continue to measure the diode data of I2C bus BB_EEPROM_SDA and BB_EEPROM_SCL that act as communication between baseband and baseband chip. The data is 650, which is normal. The circuit diagram of I2C bus is shown in picture 1-3.

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  1. Measure whether the communication circuits between CPU and baseband are normal or not. Use multimeter to measure the diode data that baseband flows to CPU signal circuits, the test points are shown in picture 1-4. We can find that the diode data of the two yellow points are infinite, as show in picture 1-5. They are the UART bus signals that run to CPU, named BB_CTS_L and BB_UART_RTS_L.

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  1. Tear down the CPU, and make sure whether it is pseudo soldering or disconnecting. After tearing it down and measuring, we find that the two solder pads are connecting to the yellow points in picture 1-5. So CPU is pseudo soldering. After reassembling CPU, we can find the firmware version in “about iPhone”.

 

Finally, the problem of iPhone 6 is removed and it back to normal work.

Ways to repair damaged motherboard on iPhone 6

No matter what we do, we must be careful, it will help us succeed. When you repair iPhone, there’s a lot of small parts here,  you maybe will  break some of these parts. There is a case, when the technical is screwing the screws of motherboard,  but accidentally the screw hole was penetrated. That caused the iPhone  can’t display when it turn on. Then repair staff  made up wires, but it doesn’t work.  Now, we can see how did vipprog fix it?

  1. Disassemble the iPhone by Screen Sucker Opening Tools, then cleaning the screw hole, we found that the two circuits under it are cut into two parts. This situation cannot be settled by scratching PCB to make up lines but to motherboard chip Copper wire . We have to use green oil to solidify the jump wires.

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  1. Finally, we need to paint all the area with added lines Green UV Fluxes Oil. Then we turn iPhone on and test it, all the function can back to normal work.

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Tips:

 

  1. As many of you do not pay attention to the strength that you use to twist the screws, the screw holes are often twisted through.

 

  1. Usually, although we can scratch PCB to make up lines wires and fix it well, we cannot to twist the screw. Fortunately, in this case, a missing screw will not affect the stability of motherboard as well as the usage of iPhone.

Resolved: iPhone 6 motherboard PCB wire broken and damaged screws

When turn on iPhone 6, it shows nothing, only dark screen. But the screen is fine, so where is the real problem? Now, let’s follow the Vipprog to find the reason and fix it.

 

  1. Disassemble the iPhone 6, we can found that three screws are twisted deep. The problems are no backlight, no display and no ±5.7V power supply of screen. Observing under VGA digital microscope, we find that the four circuits under those screws are disconnected, as shown in picture 1-1.

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  •  One of the four circuits is the open signal LCM_TO_CHESTNUT_PWR_EN of display power supply chip. This signal connects power supply chip U1202.
  • The signal LCM_TO_CHESTNUT_PWR_EN connects display power supply chip U1501.
  • The signal LCM_TO_CHESTNUT_PWR_EN connects display socket J2019 through the inductor FL2035, as shown in picture 1-2.

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  1. After measuring, display socket has no diode data, which suggests that it is disconnected. We have to jump a wire, as shown in picture 1-3.

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  1. After it can display, we measure other function and find that the receiver has no sound, but the diode data to ground of receiver is normal. Remove the audio chip (U0900) and measure the diode data. We find that pin C9 is disconnected. Pin C9 is connected to CPU (U0201), as shown in picture 1-4.

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  1. Because CPU has not been fixed before, we guess that the disconnection of the circuits under screws causes the problem. Find a bare motherboard and scratch its surface (called grinding, as shown in picture 1-5). Thus we know that the second layer (arrow in picture 1-6) under screw causes problem.

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  1. Next we jump a wire from audio chip pin C9 to the point that we find by grinding. At last, we paint UV Solder Resist  to solidify it, as shown in picture 1-7.

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  1. We skip other process of jumping wires, 10 wires in total. To operate in the same way.

Finally, after we do this all, turn on iPhone and it displays normally. The iPhone can back to normal work.

iPhone 8 is coming, are you ready?

I believed that all the fans of APPLE are looking forward to this year’s Apple launch. From 2007 to 2017,  this is the Apple’s tenth year. To celebrate the 10 anniversary,  we think the APPLE will bring us some surprises. This may focus on iPhone 8. In this page, Vipprog are going to review the history of the iPhone and introduce the information we know about iPhone 8.

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Review iPhone history
  1. 2007, the iPhone came out.
  2. 2008, iPhone 3G
  3. 2009, iPhone 3GS
  4. 2010, iPhone 4
  5. 2011, iPhone 4S
  6. 2012, iPhone 5
  7. 2013, iPhone 5S(Touch ID ) and iPhone 5C
  8. 2014, iPhone 6 / iPhone 6s Plus
  9. 2015, iPhone 6S / iPhone 6S Plus (3D touch)
  10. 2016, iPhone 6s / iPhone 6s Plus and iPhone SE
  11. 2016, iPhone 7 / iPhone 7 Plus
  12. 2017, iPhone 8 ?

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iPhone 8 News (Prediction)

  1. Release time:  if everything goes well, the iPhone 8 will be released in September 2017
  2. New design:
  •   curved AMOLED display ,edge-to-edge screen, the screen size may be around 5.8 inches
  • Touch ID will moved to the back of the iPhone 8, or remove it directly.
  • Face-scanning technology
  • Wireless charging support
  • Apple A11 chip
  • IOS 11 with improved Siri, P2P payments

……

3. Price:  with the use of new technologies and new materials, the iPhone 8 is suggested to be the most expensive iPhone Apple’s produced yet.

All information about the iPhone 8 will be confirmed after the IPhone8 release, let’s look forward to its release.

The iPhone 6S cannot boot? Here’s the solution

Nowadays, when you walk down the street, people can take photos with their phone everywhere, whether they are in the self-timer or to help others take photos. However, the phone camera function cannot be used, we urgently want to fix it, so we changed camera 2.85V power supply chip U3200, unfortunately, the phone dead immediately and won’t turn on. Please don’t worry, we can fix it.

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  1. check the standby circuits and trigger circuits, short connect it and turn it on to trigger the signal BUTTON_HOLD_HEY_CONN_L (picture 5-52), there is no current, measure the power button signal and there is 1.7V voltage, which suggests that standby circuits and trigger circuits have no problem.

Example78-1

  1. Plug in the cable to see if it can turn on. Connect adjustable power supply to energizing motherboard and use USB cable to connect iPhone and computer, but it still no response.

 

Note: based on the iPhone design principle, after plugging USB cable, iPhone will turn on automatically. If this design works, then we know that the trigger circuit is damaged. After plugging USB cable for 2s, if the current is small when turning on iPhone, the USB cable supplies it power. Therefore, we cannot see the current display on ammeter. That is to say, we cannot check the state of motherboard through current.

 

  1. Check if the CPU is pseudo soldering. Remove the shield cover and observe the surrounding area of CPU under Trinocular stereo microscope, finding no explosive tin balls and any bump on the surface of temporary storage of CPU upper board.

 

  1. Use the digital multimeter to measure the CPU power supply and MIPI bus of display and camera circuits.

 

Note: based on experience, the iPhone cannot be triggered on is because the power supply U1202 and CPU U0201 are damaged. In this way, we can judge whether CPU is short connected or pseudo soldering, and decide that power supply is fixed first or CPU first based on the measuring result.

 

  1. The diode data of the voltage of CPU power supply PP_CPU is 0 while the normal one is about 15. Observing the capacitors at the surrounding area of CPU under microscope again, we find that a filter capacitor C2001 offered power by PP_CPU turns white, which is very different from other capacitors besides it. Comparing it with the other iPhone 6S, we find that the normal capacitors are deep yellow. Pry up capacitors C2001 and measure, the diode data to ground of PP_CPU is 14. The capacitor C2001 in bitmap is shown in picture 5-53.

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  1. Finally, connect the power supply and trigger it on, the iPhone 6S can be turned on and the current back to normally. The iPhone can back to normal work and you can take photos as you want.

 

Tips:

  • The power supply of iPhone 6S will not be triggered on to protect itself when its subordinate circuits are short circuits. During the repair process, we may observe under microscope carefully to save twists and turns.

Ways to fix dead iPhone 6S after water damaged

Have you ever been met after your iPhone 6s dropped into water, then your phone dead. It’s make you crazy.  In this case, you have two choices, one is buy a new phone, another is fix this dead phone. However, i believed that most of people would like to fix it. So, let’s see what is the solution.

Solution

  1. Test the current. Connect iPhone 6S to DC power supply, check the current, it shows leakage 60mA, when we press the boot button, it shows 120mA then jump to 0mA,in the end, it repeats the jump process.

 

  1. Tear down the CPU and shield cover of baseband. We can find that it have four eroded places, they are backlight power supply chip U4020, display power supply chip U4000, charging management chip U2300 and small audio chip U3700.

 

  1. Clean the motherboard, then connect to DC power supply, the leakage current is getting smaller, about 20mA.After turning on, the current jumps from 70mA to 0mA repeatedly. Measure the power supply voltage of CPU U0600, finding no abnormality. Measure the voltage of I2C bus, finding that the signal I2C0_AP_SCL only has 1.1V. The I2C0 bus in schematic diagram is shown in picture 1-1. The I2C0 bus in bitmap is shown in picture 1-2. The material object of I2C0 bus is shown in picture 1-3.

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  1. Cut the power and use digital multimer to measure the diode data of the I2C bus, there are 404 and 430 which is normal. Viewing the eroded components photos, our preliminary judgment is that the display chip U4000 damaged, because the backlight chip is painted with glue, which is not easy to be damaged, so we remove it.

 

  1. After removing the display chip U4000, energize it, but the current is still the same. While I2C0 bus voltage turns normal. This problem may be caused by power supply chip U2000 and backlight chip U4020.That the backlight chip U4020 causes the turn on failure is related to two groups of signal. One is I2C0 bus, the other is backlight brightness adjustment signal‒backlight chip DWI bus which runs to power supply and CPU. The DWI bus interface in circuit diagram is shown in picture 1-4.

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  1. Use multimeter to measure the diode data of R4020, we find that it is short circuit. Remove the backlight chip U4020 and energize motherboard to turn it on. The current jumps to 1A. After assembling backlight chip U4020 and display chip U4000, the white Apple logo appears and iPhone gets into IOS normally. The iPhone 6S have wake up and can back to normal work.

 

Tips

 

  1. As for the water-damaged iPhones, usually need take photos first for the watered places and then clean the motherboard. That will be beneficial, because if we find some problems during the repair process, we can refer to those photos to exclude badly eroded components.

 

  1. The backlight chip DWI bus has SDI and SCK two signals. By measuring the diode data to ground, we can know whether backlight chip U4020 is workable or not. SCK can be measured at the resistor R4020 in picture 5-59 and SDI can be measured at the test point PP1002 in picture 1-6.

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  1. When dealing with the problems about the turn on failure after being watered, we can ignore the removed chips if they do not affect the turn on process. If the current jumps normally, we reassemble them. 

     

Tips for iPhone SE leakage and can’t make a phone call after water damaged

The iPhone SE has been repair after dropped in to water, all is fine but leaks 50mA and sometimes call failed. We all want to use the phone with all are fine, and then i can cut you a lot of trouble. So, let’s fix it.

Turn on the iPhone SE and test it, all the function are normal, There is signal when plug SIM card and it is normal to make calls. Tear down it and motherboard leaks 50mA. According the experience, the problems happen on the signal part. The leakage is caused by components electricity leakage on main power supply PP_VCC_MAIN circuits. And PP_VCC_MAIN supply power to all the signal power amplifiers and baseband power, power amplifier power supply chips. Thus the damage of any of them could cause electricity leakage and faulty signal.

As the motherboard has been cleaned, we cannot identify the exact watered places. Thus we use SIM cards from the three operators to test the 2G, 3G and 4G function. They all have signals. Based on the experience of 5S, call failure is often caused by the damaged power amplifier power supply chip. First remove the power amplifier power supply chip U_QPOET_RF.

Finally, we offer power to motherboard and the ammeter shows no electricity leakage. Tear a U_QPOET_RF from iPhone 6 accessories board and assemble it on the SE motherboard. Turn iPhone on and test. Calls and other functions are normal. The iPhone SE back to health.

How to fix iPhone 6 cannot turn on after water damaged? Case 3

There are many reasons to caused your iPhone 6 cannot be turn on,   two case have been mentioned before. Now, let’s introduce the third situation. The iPhone 6 won’t turn on after water damaged. The problem is the iPhone dropped into the water, then it leaks 60mA current, and then cannot turn on.

First, disassemble the screen and battery and plug adjustable power supply  to energize it. The current is 60mA. When press the power button, the current stops at about 120mA. Remove all the shield cover and find that some of capacitors of the main power supply PP_VCC_MAIN turn black.

 

According the circuit principle, we need to judge whether the electricity leakage is from the circuits of battery power supply PP_BATT_VCC or main power supply PP_VCC_MAIN.

Above all, we remove the field-effect transistor Q1403 that converts battery power supply into main power supply. The Q1403 in schematics circuit diagram is shown in picture 1.Then,plug adjustable power supply. If it still leaks, the circuits of battery power supply PP_BATT_VCC leaks. If it does not leak, the circuits of main power supply PP_VCC_MAIN leaks.

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Energize it and test. The voltage-stabilized power shows no electricity leakage. Based on repair experience, for water-damaged iPhones, we first consider display power supply IC, backlight IC and main power supply as well as capacitor (The electricity leakage from the filter capacitor at the circuits of main power supply PP_VCC_MAIN cannot lead to turn on failure).

 

Assemble Q1403 and put a thin layer of rosin on the surrounding parts of display power chip U1501 and backlight chip U1502. Then energize to find the hot components. The display power supply chip and backlight chip with rosin is shown in picture 2.

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After few minutes, we notice that the rosin is not burning. If the electricity leakage is from capacitor, function chip or baseband chip, we could fix first and then turn on to test its function. Use the problems from functional circuits to ascertain a general faulty area.

 

The motherboard has 120mA current that minus the leaked 60mA. That means when at the moment iPhone turned on, its current is 50~60mA which is caused by the damaged circuits at the working condition of CPU, I2C0 bus, I2C1 bus and large power supply chip U120.

 

Energize iPhone and measure all the power supply of CPU. All the power supply voltages are normal except the voltage PP_GPU (This voltage can be measured only when iPhone is turned on normally). Then we measure the I2C bus and find that the voltage of AP_TO_I2C0_SCL is 0.3V. This kind of trouble phenomenon can be found only by measuring the diode data to ground. If the diode data to ground of I2C bus is high while the voltage of I2C bus is low, the pull-up resistor and CPU have some problems. If the diode data to ground is pulled down or short circuit, we have to tear down the chips one by one to judge. We can measure the I2C0 bus circuit at resistors R0302 and R0303. The pull-up resistors R0302 and R0303 at I2C0 bus in bitmap are shown in picture 3.

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Deenergize iPhone and measure the diode data to ground of AP_TO_I2C0_SCL. The data is 33. I2C0 bus flows to CPU, display power supply IC, backlight power supply IC, USB chip and large power supply.

 

After water getting in, that the diode data to ground of I2C0 bus is pulled down is often caused by displays IC and USB chip. First remove display power supply U1501 and energize iPhone to test. The electricity leakage disappears. Short connect it and turn on. The adjustable power supply shows 1A current. The current jump turns normal and iPhone can be turned on normally. Remove a display power supply chip U1501 from accessories board and assemble it on this faulty motherboard. Triggering it on, the white Apple loge appears and it enters boot screen. The iPhone 6 can be turn on normally.

 

The display power supply chip U1501 in schematics diagram are shown in picture 4.

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Tips

  1. If the hot parts cannot be found, we can leave it and skip to fix the problem of turn on failure. In most cases, if the problem of turn on failure disappears, other problems will disappear too.

 

  1. If the problem of turn on failure disappears, but some function is still unworkable, we can find the faulty points by entering IOS and testing.

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