Iphone 5 dead drawing 0.1 to 0.4amps. From dc power supply

I got iphone 5 , initially it was drawing 0.40 amps from dc power supply without pressing power button so i detected short by heat detection, n find out u2 i s making it hot. I replaced the u2 now phone is drawing only between 0.1 to 0.4 amps for DCPS when i power on the phone and phone doesn’t comes on … any one know what could be the issue?

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