Help with tablet diagnosis

[Capii]

Hello guys, so i came here to ask anyone with some knowledge on tablets, especially the samsung sm-t520 or tab pro 10.1

My tablet was working perfectly until it suddenly stoppeed charging, i will tell you step by step what happened and what i did so far,

So i left it for 2 days without charge, so it went maybe about 20-24 hours without charge

went to school and plug it in wall, charging symbol appearead, closed the cover and let it sit while the class went on..

after class i just unpluged it and plugged my powerbank and went to another class, after about 1hour of charging i tried to turn it on and nothing... 

I thought that maybe the powerbank wasn't outputting enough current for it to charge, so well i just found a wall socket and plug it on, and nothing again.. no symbols on the screen it just died..

after coming home i read about it a little and found some post online saying you had to open it and unplug the LCD flat cable, the battery and the other flat cable.. did it and let it sit for about 30mins, plugged the battery and charging cable back on and charged it for about 2h, then plugged the LCD flat and tried to turn it on.. nothing again

lastly i decided to measure the voltages on the battery connector

it goes like 1,2 black 3,4 green and 5,6 red

from 1,2 to 5,6 = 2v

from 3,4 to 5,6 = 2v

any other combination results in 0

..

Can anyone help me diagnose the problem??
The most likely diagnosis i can come up with are:

1) Battery died

2) connection between the charging plug and board are dead

 

the processor or other hardware are fine i guess

but i don't want to buy a new battery and find that the problem was some other thing..

 

thanks

Capii