@count_omega ,Count Omega, Just a thought. Perhaps disassemble the phone and clean all connections(Qtip dampened 90%+ Isopropyl Alcohol) and then reset the connections to be sure of good contact and wires not pinched/broken. While phone is apart use a magnifier to inspect board/components/connectors not(loose,damage,burnt)/solder joints(cracked,etc.) and check that battery is indeed charged. Below is a disassembly link. Good luck. I hope this helped you out, if so let me know by pressing the helpful button.
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