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Hello, I’m a electronic repairer, including phones. Some days ago a client sent me a iPhone to repair, but can’t discover the inssue… When i get it, battery was dead, iphone didn’t charge it or show low power, so i removed and charged outside util is at 20%. After that i inserted again in iphone and i let iPhone charge to 100%. It charges well and fast with my 2.1A stabilized charger. iPhone itself was full of apps, location services was OFF with IOS 8.3 (If i renember well). But after the charge battery starts to drain fast, maybe 2h util reach 20% in sleep mode and airplane! I have done a full format - reset - upgrade to 9.3.1 with no success of fix. I don’t know about U2 Chip, but it charges well, fast and switch on very well. Beside that iPhone got hot when in use near apple logo, where CPU is, if i put the finger in the metal shield i can fell how hot it is. When in sleep mode is not hot, but i can fell a little warm compared to the other parts the temperature is not the same. After i tried a new battery, it survive more time but do the same symptoms… LCD have problems too, backlight blinks sometimes, touch not very resposnive, i tried to clean pins and get better at digitizer, still backlight is faulty. Backlight pins are not isolated, maybe it cause a short on metal plate? Anyone with same symptoms that can advice me? Thanks

The backlight pins, the 3 pins you are referring to that are connected to the front display cable right? Usually that has black tape but that shouldn’t cause any issues really. I’ve had a few screens with that put on iPhone 5 for client. No complaints yet about them. LCD flickering issue usually happens when you unplug the battery while the screen is on. The way to solve this is plugging the battery in. Turning the phone off and on multiple times. Have you tried another screen? The screen may be faulty in a way.

did you install a battery monitor app?

hey! I am also an electronics repair technician, and I have found that the best way to diagnose an iphone, is to remove the board from the device, and put it into an iPhone you know is functional. If it drains the battery in a similar manor, then you are looking at a mother board failure. could be a short circuit, physical damage, or just board degregation. Short of reflowing the boards solder, fixing that at a reasonable cost, is unlikely. if it does not, then you can narrow down a short in the modular components. Swapping piece for piece into the board, i like this specific order; -battery -Charge port -Screen -Frame -Front sensor -Rear camera -Power flex. I hope this helps in your diagnosis.