charges only when off

Whenever I'm connecting the charger it suddenly starts connecting and disconnecting and because of this charger tip getting too hot that you can't even touch but when I charge the battery while the laptop is off it is working perfectly fine without any issue. Model is Toshiba Satellite L50-A

Well, I have a Asus S400CA and mine suddenly starts with this problem last night (dont know what just happened). I have ubuntu 15.10 installed alongside windows 10 and the problem happens in both systems (energy system icon blinking and blinking...), when i plug the ac adapter the icon of...