3 steps to solve iPhone 6 fingerprint option shows grey and not working

Fingerprint unlock is a basic function of iPhone 6, but now the fingerprint function not working. It's really makes the owner of iPhone 6 feels bad. Turn on the iPhone and then test it, you will find that the option of fingerprint is grey and cannot be opened, as shown in picture 1-1. Anyway, let's see what's going on and how to fix it.

 

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First, disassemble the iPhone by phone opening tools, then observe it under the microscope, finding that several SMD components on the fight part of fingerprint cable are loose. After checking iPhone motherboard bitmap (picture 1-2), we know that these loose components are three inductors. Directly re-solder the three inductors, as shown in picture 1-3.

 

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Second, measure the PP1V8_MESA power supply of fingerprint cable socket 1.8V, finding no voltage. After checking the circuit diagram, we know that PP3V0_MESA gets power supply which is lowered through U2100, as shown in picture 1-4.And we find that U2100 is loose and is off its position, as shown in picture 1-5.

 

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Finally, Remount tin on U2100 and assemble it. Measure the power supply of PP1V8_MESA, which is normal. Turn on iPhone and get into IOS to test the fingerprint function. Now it is normal and iPhone 6 Touch ID back to normal work, as shown in picture 1-6.

 

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RESOLVER: iPhone 6 Plus right screen displays black

Some people must think this is very strange which the right display screen is black while the left normally displays, and when the right screen turns black, it still shows nothing after awakening it. Please calm down and first we can confirm that is not the supernatural events. Usually we called this phenomenon as yin yang screen and most of this case was caused by  abnormal backlight circuit. Now, let's see what's going on.

First, let’s start from the backlight circuit. After removing the motherboard by phone opening tools, we find that the right backlight chip is painted green UV Solder Resist and soldered a jumper wire. The wire starts from pin A1 U1580 backlight chip to the yellow point near the fingerprint socket J2118, as shown in picture 1-1.

 

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Second, the I2C bus that left backlightchip uses and the I2C bus that right backlight chip uses are not the same circuit. The left one is normal while the right one is not, even after the right backlight chip is replaced. Thus, we doubt that there is something wrong with I2C bus of the right backlight chip. The two backlight chips’ real material object are shown in picture 1-2.

 

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Third, observing the screw under microscope, we find that right and left screw holes are twisted through, as shown in picture 1-3.

 

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Finally, use knife to scratch left screw hole, we find that it still connects. While the right one disconnects, as shown in picture 1-4. Fixing the broken circuit and turn it on. The right screen of iPhone 6 Plus shows light, and your iPhone 6 Plus back to normal.

 

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The related  video link:

https://www.youtube.com/watch?v=VWto8X81PRI

How to fix ipad 4 loses touch response in particular area of screen?

The iPad 4 touch screen doesn't work with you, because it's screen has a some weird issues. The iPad 4 lost touch response in particular area of screen and could not be used normally and it has changed two brand new touch screen to test, but the problems are still the same. So, what's going on? According to the experience, we can be sure that the problems happen in motherboard.

First, turn on iPad and install the ketchpad software to test. We find that a part of vertical screen touch is unresponsive to touch. Then teardown the iPad, measure the diode data of touch screen interface by multimeter and we found that one of the data cables’ diode data is infinite, as shown in picture 1-1.

 

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Second, Opening the bitmap software, we can see that the data cable is connected with the touch screen chip and testing point TP169 at the back, as shown in picture 1-2 and 1-3.

 

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The measured diode data of test point TP160 is more than 600, as shown in picture 1-4. The data is the same as that of other cables’. Thus we conclude that there is line barrier between touch screen socket and its back.

 

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Finally, after confirming the problems, solder a wire from touch screen socket to the test point at the back, as shown in picture 1-5 and 1-6.After the jumper wire is down, restart iPad and get into IOS test. Using ketchpad software to repeatedly test the place where the original problems happen. And everything becomes normal. IPad now is working normally. Using ketchpad software to test whether the iPad now is working normally is shown in picture 1-7.

 

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How to fix touch screen not working after water damage on iPhone 6

The iPhone 6 Plus touch screen does not respond after dropping into water and the display and touch screen socket has been replaced. But it’s still not working. What can we do in this case? pls follow the Vipprog to solve it.

The touch screen circuit of iPhone 6S is quite different from that of iPhone 6. The touch control or process chips are all assembled to the display assembly. The display screen and touch screen share the same socket. The material object of iPhone 6S display and touch screen socket is shown in picture 1-1.

 

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When the display and touch chips are assembled at the screen assembly, motherboard only supplies power to touch screen circuit, clock, reset, INT signal and SPI bus. During the repair process, when iPhone has no touch problems and the displays normally after being turned on, we do not have to measure PN5V7_LCM_MESON_AVDDH, PP5V7_MESON_AVDDH and PP5V7_LCM_AVDDH. Because they are shared by display screen and touch screen. The voltage circuit diagram of display and touch screen is shown in picture 1-2.

 

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In general, we just need use multimeter to measure the diode data of part of pins of display and touch screen socket J4200. And measure the voltage of PP5V1_TOUCH_VDDH and PP1V8 after assembling display screen and turning on iPhone. The measuring points are shown as these yellow points in picture 1-3.The diode data and voltage are normal after being measured. Replace the display assembly and measure again, the touch screen still cannot respond.

 

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As iPhone 6S has the 3D touch function, the abnormal 3D touch function can cause unresponsive touch screen. 3D touch function is connected to fingerprintsocket. Thus we measure the diode data of fingerprint socket and we find the diode data of reset signal AP_TO_TOUCH_RESET_L is being a little small- just over 80. While the normal one should be about 400. After checking the bitmap, we know the reset signal AP_TO_TOUCH_RESET_L is interlinked with display and touch screen socket, as shown as the yellow points in picture 1-4. But, the diode data of AP_TO_TOUCH_RESET_CONN_L on J4200 is normal. 

 

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Finally, the measurement shows that the AP_TO_TOUCH_RESET_CONN_L on display and touch screen socket on display and touch screen socket is not linked with the AP_TO_TOUCH_RESET_CONN_L on fingerprint socket. Tear up the black adhesive tape on the edge of fingerprint socket and we can see that the several components on the edge of FL4134 and C4134 are corroded. After cleaning the corroded components, turn on iPhone and get into IOS test. The touch screen and 3D function can respond normally. The corroded components are shown in bitmap picture 1-5.

 

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