nexus 7 2013 2nd generation charging problem, slow charging

does anyone have a repair solution to this Problem.
as one can see charging is Happening every now and then but only for a few minutes - even though the charger is plugged all the time - and the Nexus also recognizes the charger being plugged at all the time.
i already replaced the battery. but had no effect.
i assume that some Hardware-component is overheating and then throttling/disabling the Charge current.