ipad 2 no power, black screen, charging at 0.24 amps?

first off we are a repair shop and have repaired thousand of i pads and i being the lead technician want answers ,this is the second iPad 2 i have had this issue. the iPad is a late 2012 a1395 model and i have had one with damage and one with out. i have opened them and inspected them under careful detail to find nothing. the iPad is completely unresponsive. it shows nothing on the screen. we have used oem chargers and cables. we have digital meters to measure the voltage and amps the device is taking. typical iPads should charge at or around 1.00 amp to 2.00 amp. the iPad is only charging at 0.24 amps witch is extremely minimal. we have tried all the usual stuff like soft resets and battery replacements. even running there logic board out side of the housing with a new battery,charge port, and screen, it has no effect. iTunes will not locate the iPad because the logic board is not fully booting up. does any one have knowledge of the this problem? or has any one had this issue?