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How to fix an iPhone touch screen that's not working, iPhone 7 touch screen Unresponsive, no matter how hard they poke or how many times they restart. In this article, vipprog explains why the touch screen on your iPhone 7 is not working, how to fix the problems by the iphone repair tools, and recommend some great repair options, if it comes to that.

 

1. iPhone Disassembling

Turn on the phone, the touch function is incapacitated. Remove charging port screws and detach the display assembly. Disconnect LCD Screen flex cables and remove iphone logic board screws. Then take out the logic board.

 

 

2. Malfunction Diagnosing

Test resistance of the display assembly connector with digital multimeter. Resistance of pin 10 displays abnormal value (470 under normal circumstances).

 

 

Roll out the maintenance drawing for reference.

 

 

 

Pin 10 worked as AP_TO _TOUCH _MAMBA _CONN _L signal. The signal was connected with CPU AT2 pin via inductor FL3904.

 

 

Circuit between pin 10 and inductor FL3904 displays normally.

 

 

Test resistance from inductor FL3904 to CPU, the device displays normal value. Then we can draw the conclusion that inductor FL3904 was damaged.

 

 

3. Malfunction Repairing

Take down the inductor with soldering iron.

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Solder tins on the copper wire. After that, connect the two bonding pads of the inductor with the iphone chip conductor wire. Then cut off the rest of it with a sculpture knife.

 

 

Test pin 10 resistance with digital multimeter again, this time we get a normal value, which means the problem has been fixed.

 

 

4. Function Testing

Clean the bonding pad with PCB Cleaning Brush.

 

 

Assemble the phone and test. Touch function is back to normal.