How to Solve iphone 6s Black Screen and Can't be Turn on

Last week, a customer send a iphone 6s to vipprog, the iPhone 6 screen turns black after standby time lasts a little longer and it is unresponsive when press the power button. Now if you have this situation you can follow this guide, and the tools used in this article can be found online at vipprogrammer.com.

ISSUE:

Immediately turning on screen after turning off is workable, but after standby time lasts a little longer, the screen is unresponsive when press the power button. The iPhone has been repaired at other maintenance shop, but the problem is still the same.

SOLUTION: 

1. Turn on iPhone and enter IOS to test all these functions. The screen turns black after standby time lasts a little longer, which may be caused by faulty functional chips and interrupt signal of power. After functional test, we find that the compass cannot be used while other functions are normal.

2. Tear iPhone down and observe motherboard, finding that the compass has been soldered and other chips are not soldered. First, fix the compass and other problems may be settled if the compass is fixed. The material object is shown in picture 1-1.

3. Remove the compass and measure the diode data of the below pins (picture 1-2). All the data is normal. 

4. Turn on the single motherboard and measure the 3.3V power supply of PP3V0_TRISTAR and 1.8V power supply of PP1V8_IMU_OWL, and they are normal. The testing points are shown in picture 1-3.

5. With normal power supply, we replace the compass chip. After replacing the chip, enter IOS to test and problems remain the same as before. Therefore, we guess that the problem may be related to SPI bus used to communicate with CPU. The compass, accelerator, gyroscope and these sensor chips of the series before iPhone 6s are managed by co-processor, such as the M8 of iPhone 6, the M7 of iPhone 5S. IPhone 6S and iPhone 6S Plus have removed co-processor and leave the work to CPU.

6. First, remove the chips that are connected with SPI bus of compass chip. These chips are baroceptor U3020, accelerator U3010 and gyroscope U3030. As the baroceptor is close to EEPROM, we can remove it without tearing the shield cover. The location of baroceptor is shown in picture 1-4.

7. After removing the baroceptor chip, the result is still the same. Next replace an accelerator to test compass which is now workable, so is the gyroscope. Turn on iPhone to standby for half an hour and then turn on screen. The screen can be turned on normally.