With that out of the way, you may want to tell more such as make and model. Those HP dv6000/9000s are well known for this issue but it appears this is some tech shop. I bet you've seen that bad one.
replaced a new power jack and know when i plug the power adapter
the fan start and stop for a few seconds than i move the cord to the left the right and start again for few seconds and stopped i tried 10 times i replaced 2 power jack the same issue .
there is a video !