My unit wont turn on

I already replaced the ac adapter with a new one and the machine still won't turn on. I don't use the unit with batteries at all as it drains the batteries very quickly.

the screen remains blank. any suggestions?

so i tested it out today with batteries and the unit turned on! Which makes me think something is wrong with the metal prong that attaches to the adapter. I also tested my adapter with my dvd player and it worked. So now I know what the problem is but can this be fixed? It looks fine to me; is not loose or broken.