FIXD: iPhone 5S screen turns black suddenly and can't be turn on
If you come across this situation that your iPhone is on, but the screen is black suddenly. Your iPhone rings, touches, has voice but you can’t answer and open. You’ve tried resetting your iPhone, letting it run out of battery and plugging it back in, and your iPhone screen is still black. The black screen is usually caused by a hardware problem with your iPhone 5s. In this article, I’ll explain what you can do to fix it.
The tools that you need:
Trouble Phenomenon:
Customer said that his iPhone 5S screen suddenly turns black when he played with it at night and it cannot be turned on since then.
Repair Process:
1. We use a adjustable power supply to charge it and charger shows 4.28 A current flow (picture 1-1), which is an obvious shout circuit. Use multimter to measure the diode data to ground of battery interface, which is normal. We continue to measure and find that the main power supply PP_VCC_MAIN is short circuit to ground.
2. Observing under microscope, we find no abnormality on the surface of capacitors on the circuits connected with PP_VCC_MAIN. We use burn-in method to check the faulty points, using an electric soldering iron to light rosin on the circuits. We find a capacitor under CPU is extremely hot and it burn out the rosin. The capacitor’s color changes from white to transparent, as shown in picture 1-2. The discolored capacitor is shown in picture 1-3.
3. After checking the circuit diagram, we know that the location number of short circuit capacitor is C358, as shown in picture 1-4.
4. Use air gun(VIP321) to remove C358 and use multimter to measure the diode data to ground of the two ends of C358, which is 0, as shown in picture 1-5.
5. After removing the capacitor, measure the diode data to ground of PP_VCC_MAIN, which is normal. Plug the adjustable power supply and the standby is normal. Triggering it on, the current change is normal. Assemble it on iPhone and test other functions, finding no abnormality.
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