GT 9505 not charging after usb/flex cable change

So my friend asked me if i could look up why his GT I9505 wont charge.
I changed flex/usb cable and checked all twice i got correct.

Put on charger and wont turn on or show signs of chargeing.
But after 20min on usb charger it gets bit hot around camera.

So is my new flex/usb replacement DOA or its fine?