How to replace power jack?

My UE Boombox (the big blue and grey one, not the mobile Boombox) stopped charging it's battery

I have changed my battery and bought a new power adapter so these two are not the problem. The battery gets discharged and I can't charge it back up.

So the question is: what and where should I look for as power jack goes? Also, is it possible to replace it myself as I have never worked on a circuit board.

Thanks