Xperia z charging issue

Hi everyone,
My xperia z is frustrating me with its charging issue. At first I thought it to be its charging port problem, so i changed it. But it doesn’t work. When I connect to it charger, it starts charging but only for some time like it goes upto 5% of charge and then charging stops. After this even if I reconnect it, it doesn’t show charging. All i have to do is to disconnect its battery and then reconnect again so that it can take up charging again. but again it happens the same…again and again…
I looked on the board with a magnifier so as to find any disfigured component, but could not find any. All I think is that there might be any problem with some capacitor like components which doesnt allow current flow once it is fully charged.
So, where should i look for or what should i do now ?
And sorry I dont have any formal education in electronics or complex integrated circuits
any suggestion is highly appreciated
waiting for you replies