Chosen Solution
My iPhone won’t turn on after battery replacement. I have looked many places and tried many things. Story: My iPhone broke so we bought a cheap one from online, took the phone apart and put the battery following a guide exactly except I mixed up the battery casing and screen connector casing screws so I sorted those out as best I could and put it back together. Nothing, screen didn’t work, couldn’t get any response from the vibrator, after a long charge same thing, except I did feel the phone warm while it charged. Thought it was a defective battery and bought a good one from iFixIt. Replaced it and was extra carful to make sure this time was errorless Put it back together, screen didn’t turn on again, same issue. Charged for a couple hours, nothing didn’t even warm up the phone, no iTunes response either. Facts I’m pretty sure of: Battery is ok (came from iFixIt)Battery to charging port is ok (First battery warmed the phone (second battery was probably full))Screen is possibly not broken (Not getting a response from anything not even the vibration so that doesn’t mean it’s just the screen) Things I’ve already tried: Quadruple check that all cables connectors are securely in place.Let it charge for a whilePressing Power and Home buttons for 10+ seconds, and home for 3 thenTried unplugging battery and plugging into iTunesTried disconnecting the battery and reconnecting Not tried: Screen replacement3rd batteryAny other motherboard part replacements Any and all suggestions appreciated! Problem found! It was the screen, I must have damaged it while replacing the battery.
Do you know if the battery in the “used” phone was charged or not? It is possible that it is fully depleted. You could measure the voltage of the battery directly with a multimeter. A normal battery is ~3.8V, fully charged at 4.2V and the phone will not boot if it is below ~3V. I’m also a little bit concerned about you mixing up the screws on the Screen bracket. Putting a long screw in the wrong hole can cause Long Screw Damage although in this case, your immediate symptoms don’t correspond.
